Getting ahead of Alzheimer's and Parkinson's

The short version

None of the trials below shows that any change prevents either disease.^1,2,3 What exists is a list of risk factors, a few trials that nudged cognitive scores, one natural experiment that ties a shingles vaccine to fewer dementia diagnoses⁴, and new tests that spot the disease earlier.
The 2024 Lancet Commission on dementia names 14 modifiable risk factors and estimates that 45% of cases could potentially be delayed or reduced. I couldn't read the report itself, so those figures come from two secondary summaries of it, and the estimate assumes the factors cause dementia. It describes populations, not any one person.^5,6,7
The best lifestyle trials (FINGER and US POINTER) beat a comparison group by a small margin on a cognition score. Neither lasted long enough to show fewer diagnoses.^1,2
For Parkinson's, the exposures studied here are pesticides, the solvent trichloroethylene, and head injury, all in observational studies. Two early warning signs are acting out dreams and losing the sense of smell, and newer tests can find the abnormal protein, alpha-synuclein, in spinal fluid or a skin biopsy.^{8,9,10,11,12,13}
I train, use a sauna, and follow keto. I say below where each one does and does not touch this list. I'm not a doctor, and this is what I read, not advice.

The protocol

There isn't one, and I'd be lying if I wrote one. This is the list the research points at, with what each item has actually been tested for.

Factor	What the research tested	Source
Blood pressure	Intensive systolic target under 120 mm Hg versus under 140, in adults 50 and older with high blood pressure	³
Hearing	Hearing aids and counseling versus health education, in adults 70 to 84 with untreated hearing loss	¹⁴
Exercise	Aerobic training in 120 older adults, with hippocampal volume as the outcome	¹⁵
Multiple factors at once	Diet, exercise, brain training, and vascular checks for 2 years	^1,2
Shingles vaccine	Eligibility for the live shingles vaccine, set by a date-of-birth cutoff in Wales	⁴
Sleep	One night without sleep, with brain amyloid measured on PET	¹⁶

Those are what each study tested, not doses I'm recommending. Medicines like blood pressure drugs are a decision for a doctor.

Why it works

The honest answer is that nobody knows for sure, so I'll stick to what the sources say.

The Commission's list covers the whole life span. Less education matters most in early life, high LDL cholesterol counts in midlife from around age 40, and social isolation, air pollution, and untreated vision loss count most in later life.^6,7

For exercise, the trial found a 2% increase in the size of one part of the hippocampus, which the authors say reverses about 1 to 2 years of age-related loss. They also found that larger hippocampal volume went with higher serum BDNF, a protein tied to growing new neurons.¹⁵ That is a measurement of brain size and memory, not a count of diagnoses.

For sleep, one small experiment found amyloid went up after a night without sleep, which fits the idea that sleep affects amyloid, but it is 20 people and one night.¹⁶

What the research says

Moderate The 2024 Lancet Commission counts 14 modifiable risk factors for dementia, adding high LDL cholesterol and untreated vision loss to the 12 on its 2020 list.^6,7 The 14 are less education, hearing impairment, high blood pressure, smoking, obesity, depression, physical inactivity, diabetes, excessive alcohol, traumatic brain injury, air pollution, social isolation, high LDL cholesterol, and untreated vision loss.⁷ In its estimate, high LDL and hearing impairment each account for 7% of cases, untreated vision loss for 2%, and the 12 older factors together for about 40%.⁷ The 45% headline assumes the factors cause dementia, the authors say some links may be only partly causal, and they note it does not guarantee that any individual avoids dementia.^6,7 The report's PubMed record has no abstract and I couldn't open the full text, so every figure in this paragraph comes from two secondary summaries: a news item from Alzheimer's Disease International and an article on News-Medical.⁵

Moderate FINGER randomized 1,260 Finnish adults aged 60 to 77 at higher dementia risk to two years of diet, exercise, brain training, and vascular monitoring, or to general health advice. On a standardized test-battery score, the program group improved by 0.022 a year more than the control group (95% CI 0.002 to 0.042), and adverse events, mostly musculoskeletal pain, occurred in 7% versus 1%.¹ That is statistically real and small.

Moderate US POINTER randomized 2,111 sedentary adults aged 60 to 79 at higher risk of decline to a structured or a self-guided lifestyle program for two years. Both groups improved on a global cognition score (0.243 versus 0.213 SD a year), and the structured group's edge was 0.029 SD a year (95% CI 0.008 to 0.050).² The benefit looked the same in APOE e4 carriers and noncarriers.² Since both arms improved and there was no do-nothing group, I read this as "intensive support beats lighter support by a little," not "lifestyle reverses decline."

Moderate Blood pressure: SPRINT MIND randomized 9,361 adults 50 and older with high blood pressure (and no diabetes or prior stroke) to a systolic target under 120 or under 140 mm Hg. Probable dementia was 7.2 versus 8.6 cases per 1,000 person-years, a hazard ratio of 0.83 that missed significance (95% CI 0.67 to 1.04).³ Mild cognitive impairment fell (HR 0.81, 95% CI 0.69 to 0.95), and so did the combined outcome of either one (HR 0.85, 95% CI 0.74 to 0.97).³ The trial stopped early for its heart results, and with fewer dementia cases than expected it may have been underpowered for dementia.³ In trials, lowering blood pressure also cuts strokes and coronary heart disease, which matters whatever it does for the brain.¹⁷

Mixed Hearing: ACHIEVE randomized 977 adults aged 70 to 84 with untreated hearing loss to hearing aids and counseling or to health education for three years. Cognitive change did not differ overall (-0.200 versus -0.202 SD).¹⁴ The effect differed between the two groups they recruited from (interaction p=0.010), which the authors read as a possible benefit in people at higher risk of decline.¹⁴ Hearing loss is one of the Commission's two biggest factors (7% of cases in its estimate), so with a null main result I'd call this unsettled.⁷

Early Exercise and the hippocampus: in a randomized trial of 120 older adults, aerobic training increased the size of the anterior hippocampus by 2%, and the authors tie that gain to better spatial memory; volume declined in the control group.¹⁵ The activity guideline most adults are told to follow, 150 to 300 minutes a week of moderate activity, is a general health standard, not a dementia dose.¹⁸

Moderate Shingles vaccine: in Wales, people born on or after September 2, 1933 became eligible for the live shingles vaccine and people born before that date never did, which makes the two groups close to randomized. Uptake was 47.2% versus 0.01% for people one week on either side of the cutoff, and over seven years the vaccine lowered the chance of a new dementia diagnosis by 3.5 percentage points (95% CI 0.6 to 7.1), a 20.0% relative reduction, with a stronger effect in women.⁴ It is still observational: a natural experiment on health records, not a trial that assigned the vaccine.⁴

Early Sleep and amyloid: 20 healthy adults had more beta-amyloid in the right hippocampus and thalamus after one night without sleep, and higher baseline amyloid went with fewer reported hours of sleep a night.¹⁶ Sleep is not on the Commission's 14, and one night with no sleep is not the same as sleeping less every night, so I'm not claiming it causes anything.⁷

Early Sauna: in 2,315 Finnish men, 4 to 7 sessions a week went with lower dementia and Alzheimer's risk than once a week (hazard ratios 0.34 and 0.35), on only 204 and 123 cases.¹⁹ It is an association from the same Finnish cohort as the sauna mortality paper, and the sauna page covers the caveats.¹⁹

Early detection

Alzheimer's. In May 2025 the FDA cleared the first blood test used in diagnosing it, the Lumipulse G pTau217/beta-amyloid 1-42 plasma ratio, for adults 55 and older who already have signs and symptoms.²⁰ In 499 samples from cognitively impaired adults, 91.7% of people with positive results had amyloid confirmed by PET or spinal fluid, 97.3% of people with negative results were confirmed negative, and fewer than 20% got an indeterminate result.²⁰ The FDA says it is not a screening test or a stand-alone diagnosis.²⁰ A Swedish study of 1,213 patients with cognitive symptoms, in primary care (307 and 208 patients) and secondary care (300 and 398 patients), found 88% to 92% accuracy for a blood test built on p-tau217. Primary care doctors identified clinical Alzheimer's correctly 61% of the time after their usual workup, versus 91% for the test.²¹ All of it is in people who already have symptoms; I did not find a cleared test for people without symptoms who want to know their future risk.

Parkinson's. Two signs can show up years before the shaking. In 1,280 people with REM sleep behavior disorder (acting out dreams) confirmed by a sleep study, 6.3% a year went on to a full neurodegenerative disease, parkinsonism or dementia, and 73.5% had by 12 years; a poor sense of smell raised that hazard 2.62-fold.¹¹ A spinal fluid test called an alpha-synuclein seed amplification assay picked up the misfolded protein with 87.7% sensitivity for Parkinson's and 96.3% specificity, and it was positive in 44 of 51 people with early warning signs (acting out dreams or loss of smell).¹² That study was a single snapshot and did not follow people to see who developed Parkinson's.¹² A skin biopsy found the abnormal protein in 92.7% (89 of 96) of people with Parkinson's and 3.3% (4 of 120) of controls. Everyone tested either already had a diagnosis or was a control, and the authors say it still needs testing in unselected patients.¹³ I did not check how widely either test is offered outside research and specialist clinics, and none of these studies tested whether knowing early changes the outcome.

What the Parkinson's research says

Early Exercise for people who already have it: in the SPARX phase 2 trial, 128 people within 5 years of diagnosis and not yet on medication were randomized to high- or moderate-intensity treadmill exercise or a wait-list for 6 months. The high-intensity group's motor score changed by 0.3 points versus 3.2 points of worsening in the controls (P = .03).²² A phase 3 trial, SPARX3, has enrolled 370 people and lists an estimated primary completion of July 31, 2027, as of its July 2026 registry update.²³ That is about symptoms in people who already have the disease, not prevention, and six months can't show whether exercise slows it.

Early Pesticides: in a case-control study nested in the Agricultural Health Study, which enrolled licensed pesticide applicators (mostly farmers) and their spouses, rotenone and paraquat use each had an odds ratio of 2.5 for Parkinson's.⁸ It had 110 cases and 358 controls, and it is an association among people who used these chemicals on farms.⁸

Early Trichloroethylene (TCE): in 99 twin pairs where only one twin had Parkinson's, TCE exposure had an odds ratio of 6.1 (95% CI 1.2 to 33).⁹ That interval is huge, and the authors say the finding needs replication.⁹ As of the EPA's page updated October 22, 2026, a final TCE rule was issued in December 2024, and on October 14, 2026 the agency proposed moving some compliance dates to December 31, 2027, with the ban staying in place. The page doesn't mention Parkinson's.²⁴

Moderate Head injury: a meta-analysis of 22 observational studies found a pooled odds ratio of 1.57 (95% CI 1.35 to 1.83) for Parkinson's after a head injury that caused a concussion.¹⁰ Nineteen of the 22 were case-control studies, which depend on people remembering old injuries.¹⁰

Rhonda Patrick on Alzheimer's, APOE4, and DHA

Rhonda Patrick, PhD, has written and talked about this. What I can verify, and no more:

Her 2019 FASEB Journal paper proposes that APOE4 carriers have impaired brain uptake of free DHA but not of DHA bound to a phospholipid, and that dietary DHA in phospholipid form could lower Alzheimer's risk. It's a hypothesis paper with no participants or data.²⁵
The show notes for her seventh appearance on the Joe Rogan Experience (December 21, 2017) say fish roe and krill oil are rich in phospholipid DHA, that this form passes into the brain more readily, and that it may be beneficial for people with APOE-related Alzheimer's.²⁶
Her members-only Aliquot #82, "Reducing Alzheimer's Risk for APOE4 Carriers" (March 23, 2023), says on its public page that lifestyle factors can temper some of the risk of carrying APOE4. Its chapters cover exercise, diet, education, sleep, alcohol, air pollution, and one titled "Can someone with an APOE4 genotype follow a ketogenic diet?" I haven't heard it, so I can't say what she concludes.²⁷
She has covered sauna and Alzheimer's risk with Jari Laukkanen, lead author of the Finnish sauna studies.²⁸ In a January 2026 talk she tied heat shock proteins to protection against amyloid-beta buildup in mouse models. I treat that as a mechanism, not a result.²⁹
The Peter Attia Drive episode #252 with her is titled as covering Alzheimer's disease, though the detail sits behind a paywall.³⁰

None of that is an endorsement of anything I do. DHA for APOE4 carriers is a proposal, and I haven't found a trial that tests it.

How I use it

Here is how what I do lines up with the list:

Training matches the physical-inactivity item and the hippocampus result. The research on this page doesn't say how much is enough for the brain.^15,18 The training page covers the training evidence.
Sauna has the Finnish dementia association, which is early.¹⁹
Keto matters here because high LDL is on the Commission's list.⁷ One study of 80 people on keto with very high LDL found no more coronary plaque than in matched controls, and LDL as a cause of artery disease is well established.^31,32 The keto page and the heart page cover LDL in detail. I don't have my lipid numbers on this page yet.
Creatine has small trials on cognition in healthy people with mixed results, and none on dementia prevention that I've cited.³³
Sleep: I usually get 4.5 to 6 hours a night. The study above tested one night with no sleep, not a pattern like mine, but its finding that people who reported fewer hours had more amyloid at baseline points the wrong way for me, and it's only 20 people.¹⁶
I also take Nuvigil and retatrutide, and I do a 3-day water and broth fast once a month. I didn't research those for this page, and none of the trials above tested them.

Cautions

The 45% assumes the risk factors cause dementia, and it describes populations, not a personal forecast.^6,7
The lifestyle trials here ran two years, and amyloid plaques can show up years before symptoms, so small score gains are not fewer diagnoses.^1,2,20
The cleared Alzheimer's blood test is for people with symptoms, and the FDA says it is not a screening test.²⁰
The spinal fluid test study was a snapshot, so it can't say whether or when a positive result leads to Parkinson's.¹²
Blood pressure drugs, and anything that touches sleep, are decisions for a doctor.
I'm not a doctor, and this is what I read, not medical advice. If you have symptoms, a neurologist is the person to see.

References

Ngandu T, Lehtisalo J, Solomon A, Levälahti E, Ahtiluoto S, Antikainen R, et al. A 2 year multidomain intervention of diet, exercise, cognitive training, and vascular risk monitoring versus control to prevent cognitive decline in at-risk elderly people (FINGER): a randomised controlled trial. Lancet (London, England). 2015;385(9984):2255-2263.Randomized trialPubMed 25771249 · DOI
What it found: FINGER randomized 1,260 people aged 60 to 77 at elevated dementia risk to a 2-year program of diet, exercise, cognitive training, and vascular risk monitoring (631) or general health advice (629). The cognitive test score rose 0.022 per year more in the program group (95% CI 0.002 to 0.042, p=0.030), and adverse events (mostly musculoskeletal pain) occurred in 46 (7%) versus 6 (1%).
Limits: Two years is too short to show fewer dementia diagnoses, and the gain was small on a test battery, in a Finnish population selected for higher risk.
Baker LD, Espeland MA, Whitmer RA, Snyder HM, Leng X, Lovato L, et al. Structured vs Self-Guided Multidomain Lifestyle Interventions for Global Cognitive Function: The US POINTER Randomized Clinical Trial. JAMA. 2025;334(8):681-691.Randomized trialPubMed 40720610 · DOI
What it found: US POINTER randomized 2,111 older adults (mean age 68.2 years) at 5 US sites to a structured lifestyle program (1,056) or a self-guided one (1,055) for 2 years. A global cognition score rose in both groups (0.243 versus 0.213 SD per year), a difference of 0.029 SD per year (95% CI 0.008 to 0.050, P = .008), and the benefit was consistent in APOE e4 carriers and noncarriers (P = .95 for interaction).
Limits: Both groups improved and the gap between them is small, it compares two lifestyle programs with no true no-intervention group, and two years cannot show fewer dementia cases.
SPRINT MIND Investigators for the SPRINT Research Group, Williamson JD, Pajewski NM, Auchus AP, Bryan RN, Chelune G, et al. Effect of Intensive vs Standard Blood Pressure Control on Probable Dementia: A Randomized Clinical Trial. JAMA. 2019;321(6):553-561.Randomized trialPubMed 30688979 · DOI
What it found: SPRINT MIND randomized 9,361 adults aged 50 or older with hypertension (mean age 67.9) to a systolic target under 120 or under 140 mm Hg. Probable dementia was 7.2 versus 8.6 per 1,000 person-years (HR 0.83, 95% CI 0.67 to 1.04, not significant), while mild cognitive impairment fell (HR 0.81, 95% CI 0.69 to 0.95) and the combined outcome fell (HR 0.85, 95% CI 0.74 to 0.97).
Limits: The primary dementia result was not statistically significant, the trial stopped early for cardiovascular benefit with fewer dementia cases than expected, and people with diabetes or prior stroke were excluded.
Eyting M, Xie M, Michalik F, Heß S, Chung S, Geldsetzer P. A natural experiment on the effect of herpes zoster vaccination on dementia. Nature. 2025;641(8062):438-446.Cohort studyPubMed 40175543 · DOI
What it found: A regression discontinuity analysis of Welsh health records, using a rule that made people born on or after 2 September 1933 eligible for the zoster vaccine for at least a year (uptake 47.2% versus 0.01% one week either side of the cutoff). Over 7 years vaccination lowered the chance of a new dementia diagnosis by 3.5 percentage points (95% CI 0.6 to 7.1, P = 0.019), a 20.0% relative reduction, with a stronger effect in women than men.
Limits: A natural experiment on health records, not a randomized trial, so it estimates the effect of being eligible for one vaccine in one country and cannot say how it works.
Livingston G, Huntley J, Liu KY, Costafreda SG, Selbæk G, Alladi S, et al. Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission. Lancet (London, England). 2024;404(10452):572-628.ReviewPubMed 39096926 · DOI
What it found: The 2024 report of the Lancet standing Commission on dementia prevention, intervention, and care, the source of the risk-factor list on the page. Its PubMed record has no abstract, so the page takes its figures from two secondary summaries (adi2024lancet and newsmedical2024lancet), not from this record.
Limits: I could not open the full text, so the page cites the report's conclusions only through two summaries of it, and its preventable share is an estimate that assumes the risk factors are causal.
Alzheimer's Disease International. Lancet Commission identifies two new risk factors for dementia and suggests 45% of cases could be delayed or reduced. Alzheimer's Disease International (news), August 1, 2024.ArticleRead
What it found: News item on the 2024 Lancet Commission: 45% of dementia cases could potentially be delayed or reduced, a 5% increase from the 2020 findings, and two new risk factors, failing eyesight and elevated LDL cholesterol, bring the total to 14. Less education has the greatest impact in early life, and social isolation, air pollution, and vision loss in late life.
Limits: A news summary by an advocacy organization, not the report itself, and it does not list all 14 factors.
News-Medical. Targeting 14 modifiable risk factors from childhood to old age could prevent or delay dementia. News-Medical.net, August 1, 2024.ArticleRead
What it found: News summary of the 2024 Lancet Commission listing the 14 modifiable risk factors (less education, hearing impairment, high blood pressure, smoking, obesity, depression, physical inactivity, diabetes, excessive alcohol, traumatic brain injury, air pollution, social isolation, high LDL cholesterol, and untreated vision loss), with high LDL and hearing impairment at 7% of cases each, untreated vision loss at 2%, and the 12 older factors at about 40%. It says the estimates assume the risk factors are causal and do not guarantee that any individual will avoid dementia.
Limits: A secondary news summary, not the report itself; it gives life stages for only some factors and does not state the overall preventable share, which the page cites to the ADI summary.
Tanner CM, Kamel F, Ross GW, Hoppin JA, Goldman SM, Korell M, et al. Rotenone, paraquat, and Parkinson's disease. Environmental Health Perspectives. 2011;119(6):866-872.Cohort studyPubMed 21269927 · DOI
What it found: A case-control study nested in the Agricultural Health Study with 110 Parkinson's cases and 358 controls: rotenone use had an odds ratio of 2.5 (95% CI 1.3 to 4.7) and paraquat 2.5 (95% CI 1.4 to 4.7), and pesticides that inhibit mitochondrial complex I (OR 1.7) or cause oxidative stress (OR 2.0) were also associated.
Limits: A small case-control study of licensed pesticide applicators (mostly farmers) and their spouses, so it shows an association with farm use and says nothing about lower exposures such as diet or living near a farm.
Goldman SM, Quinlan PJ, Ross GW, Marras C, Meng C, Bhudhikanok GS, et al. Solvent exposures and Parkinson disease risk in twins. Annals of Neurology. 2012;71(6):776-784.Cohort studyPubMed 22083847 · DOI
What it found: Ninety-nine twin pairs discordant for Parkinson's disease, from a World War II veteran twin cohort, with solvent exposure estimated by raters blind to case status. Trichloroethylene exposure was associated with Parkinson's disease (OR 6.1, 95% CI 1.2 to 33, p = 0.034), perchloroethylene showed a trend (OR 10.5, 95% CI 0.97 to 113, p = 0.053), and the authors say replication is needed.
Limits: Small, with very wide confidence intervals, and exposure was estimated from work and hobby histories decades later.
Jafari S, Etminan M, Aminzadeh F, Samii A. Head injury and risk of Parkinson disease: a systematic review and meta-analysis. Movement Disorders. 2013;28(9):1222-1229.Meta-analysisPubMed 23609436 · DOI
What it found: Meta-analysis of 22 observational studies (19 case-control, 2 nested case-control, 1 cohort): a history of head trauma causing concussion went with a pooled adjusted odds ratio of 1.57 (95% CI 1.35 to 1.83) for Parkinson's disease.
Limits: Mostly case-control studies, which depend on people recalling old injuries, so it shows an association and cannot rule out that early disease made falls more likely.
Postuma RB, Iranzo A, Hu M, Högl B, Boeve BF, Manni R, et al. Risk and predictors of dementia and parkinsonism in idiopathic REM sleep behaviour disorder: a multicentre study. Brain. 2019;142(3):744-759.Cohort studyPubMed 30789229 · DOI
What it found: Multicenter cohort of 1,280 people with polysomnography-confirmed idiopathic REM sleep behavior disorder followed a mean 4.6 years: 6.3% per year converted to an overt neurodegenerative syndrome, and 73.5% had converted by 12 years. An olfactory deficit predicted conversion (hazard ratio 2.62), as did abnormal quantitative motor testing (3.16), and the authors estimate 142 to 366 patients per arm for definitive neuroprotective trials.
Limits: People with sleep-study-confirmed REM sleep behavior disorder at 24 centers of an international research group, so it does not give the risk for everyone who has a poor sense of smell or occasionally acts out dreams.
Siderowf A, Concha-Marambio L, Lafontant DE, Farris CM, Ma Y, Urenia PA, et al. Assessment of heterogeneity among participants in the Parkinson's Progression Markers Initiative cohort using α-synuclein seed amplification: a cross-sectional study. The Lancet. Neurology. 2023;22(5):407-417.Cross-sectional studyPubMed 37059509 · DOI
What it found: Cross-sectional analysis of 1,123 PPMI participants: the alpha-synuclein seed amplification assay had 87.7% sensitivity for Parkinson's disease (95% CI 84.9 to 90.5) and 96.3% specificity versus healthy controls. It was positive in 44 of 51 prodromal participants with REM sleep behavior disorder or loss of smell, and in 25 of 310 non-manifesting LRRK2 or GBA variant carriers.
Limits: A research cohort tested at one time point, so it shows the assay can sort groups but not what a positive result means for any one person without symptoms.
Gibbons CH, Levine T, Adler C, Bellaire B, Wang N, Stohl J, et al. Skin Biopsy Detection of Phosphorylated α-Synuclein in Patients With Synucleinopathies. JAMA. 2024;331(15):1298-1306.Cross-sectional studyPubMed 38506839 · DOI
What it found: Blinded cross-sectional study at 30 sites (343 in the primary analysis: 223 with a synucleinopathy, 120 controls). Skin biopsy found phosphorylated alpha-synuclein in 92.7% (89/96) of people with Parkinson's disease, 98.2% (54/55) with multiple system atrophy, 96.0% (48/50) with dementia with Lewy bodies, and 3.3% (4/120) of controls.
Limits: People who already had a diagnosis and controls, tested once, so it does not show how well a skin biopsy predicts disease in someone without symptoms; the lead author holds stock options in CND Life Sciences, whose staff provided logistical support.
Lin FR, Pike JR, Albert MS, Arnold M, Burgard S, Chisolm T, et al. Hearing intervention versus health education control to reduce cognitive decline in older adults with hearing loss in the USA (ACHIEVE): a multicentre, randomised controlled trial. The Lancet (London, England). 2023;402(10404):786-797.Randomized trialPubMed 37478886 · DOI
What it found: ACHIEVE randomized 977 adults aged 70 to 84 with untreated hearing loss (490 to hearing aids and counseling, 487 to health education) for 3 years. The primary outcome, 3-year change in global cognition, did not differ (-0.200 versus -0.202 SD, difference 0.002, 95% CI -0.077 to 0.081, p=0.96), though the effect differed between the two recruited cohorts (interaction p=0.010).
Limits: The overall result was null and unmasked, and the possible benefit in the higher-risk cohort comes from a subgroup comparison that the authors present as a suggestion.
Erickson KI, Voss MW, Prakash RS, Basak C, Szabo A, Chaddock L, et al. Exercise training increases size of hippocampus and improves memory. Proceedings of the National Academy of Sciences of the United States of America. 2011;108(7):3017-3022.Randomized trialPubMed 21282661 · DOI
What it found: Randomized controlled trial of 120 older adults: aerobic exercise training increased anterior hippocampal volume by 2%, offsetting roughly 1 to 2 years of age-related loss, and improved spatial memory. Higher serum BDNF went with larger hippocampal volume, and volume shrank in the control group.
Limits: A brain-imaging and memory-test result in 120 people, not proof that exercise prevents dementia, and the abstract does not say how long the training lasted.
Shokri-Kojori E, Wang GJ, Wiers CE, Demiral SB, Guo M, Kim SW, et al. β-Amyloid accumulation in the human brain after one night of sleep deprivation. Proceedings of the National Academy of Sciences of the United States of America. 2018;115(17):4483-4488.Lab or mechanistic studyPubMed 29632177 · DOI
What it found: PET imaging in 20 healthy adults compared brain beta-amyloid after a night of rested sleep and after one night without sleep. Amyloid burden rose significantly in the right hippocampus and thalamus after sleep deprivation, and higher baseline amyloid in several regions went with fewer reported hours of sleep per night.
Limits: Twenty healthy adults and one night of lost sleep, so it shows a short-term amyloid change on PET and not that poor sleep causes Alzheimer's.
Ettehad D, Emdin CA, Kiran A, Anderson SG, Callender T, Emberson J, et al. Blood pressure lowering for prevention of cardiovascular disease and death: a systematic review and meta-analysis. Lancet (London, England). 2016;387(10022):957-967.Meta-analysisPubMed 26724178 · DOI
What it found: Meta-analysis of 123 trials with 613,815 participants. Each 10 mm Hg lower systolic pressure cut major cardiovascular events (RR 0.80, 95% CI 0.77 to 0.83), coronary heart disease (0.83), stroke (0.73), heart failure (0.72), and all-cause mortality (0.87, 0.84 to 0.91).
Limits: Pools trials of drug treatment, so it shows what lowering pressure with medication does, not what diet or exercise alone would do.
Bull FC, Al-Ansari SS, Biddle S, Borodulin K, Buman MP, Cardon G, et al. World Health Organization 2020 guidelines on physical activity and sedentary behaviour. British Journal of Sports Medicine. 2020;54(24):1451-1462.GuidelinePubMed 33239350 · DOI
What it found: WHO guideline for adults: 150 to 300 minutes a week of moderate activity, or 75 to 150 minutes of vigorous activity, or an equivalent mix, plus regular muscle-strengthening and less sedentary time.
Limits: A population guideline for general health, not a plan for building an athlete, and the evidence was too thin to set a sitting-time limit.
Laukkanen T, Kunutsor S, Kauhanen J, Laukkanen JA. Sauna bathing is inversely associated with dementia and Alzheimer's disease in middle-aged Finnish men. Age and Ageing. 2017;46(2):245-249.Cohort studyPubMed 27932366 · DOI
What it found: Prospective cohort of 2,315 men aged 42 to 60 followed a median of 20.7 years, with 204 dementia cases and 123 Alzheimer's cases. Compared with one session a week, 4 to 7 sessions a week had a dementia hazard ratio of 0.34 (95% CI 0.16 to 0.71) and an Alzheimer's hazard ratio of 0.35 (0.14 to 0.90); 2 to 3 sessions a week was not significant (0.78, 0.57 to 1.06, for dementia).
Limits: Observational, men only, relatively few cases, and the same Finnish cohort as the mortality paper, so it is not an independent confirmation and cannot show causation.
U.S. Food and Drug Administration. FDA Clears First Blood Test Used in Diagnosing Alzheimer's Disease. FDA News Release, May 16, 2025.Regulatory noticeRead
What it found: FDA cleared the Lumipulse G pTau217/beta-Amyloid 1-42 Plasma Ratio test (Fujirebio) for adults aged 55 and older with signs and symptoms of Alzheimer's disease. In a study of 499 plasma samples, 91.7% of positive results had amyloid confirmed by PET or CSF and 97.3% of negative results were confirmed negative, with fewer than 20% indeterminate.
Limits: The FDA says the test is not intended as a screening or stand-alone diagnostic test, and it was studied in people who already had cognitive impairment.
Palmqvist S, Tideman P, Mattsson-Carlgren N, Schindler SE, Smith R, Ossenkoppele R, et al. Blood Biomarkers to Detect Alzheimer Disease in Primary Care and Secondary Care. JAMA. 2024;332(15):1245-1257.Cohort studyPubMed 39068545 · DOI
What it found: A Swedish prospective study of 1,213 patients with cognitive symptoms applied fixed plasma p-tau217 cutoffs in primary care (307 and 208 patients) and secondary care (300 and 398 patients) cohorts. Accuracy for Alzheimer's pathology was 88% to 92% (AUC 0.96 to 0.97), and for clinical Alzheimer's, primary care physicians' accuracy was 61% and dementia specialists' 73%, versus 91% for the blood test.
Limits: Observational, in people who already had cognitive symptoms and were referred, so it does not show how the test performs as a screen in people without symptoms.
Schenkman M, Moore CG, Kohrt WM, Hall DA, Delitto A, Comella CL, et al. Effect of High-Intensity Treadmill Exercise on Motor Symptoms in Patients With De Novo Parkinson Disease: A Phase 2 Randomized Clinical Trial. JAMA Neurology. 2018;75(2):219-226.Randomized trialPubMed 29228079 · DOI
What it found: SPARX phase 2 randomized 128 people within 5 years of a Parkinson's diagnosis and not on dopaminergic medication (43 high-intensity, 45 moderate-intensity, 40 wait-list control) to treadmill exercise for 6 months. The motor score changed by 0.3 points with high-intensity exercise (about 80.2% of maximum heart rate, 2.8 days a week) versus 3.2 points of worsening in controls (P = .03), and only the high-intensity group cleared the futility threshold.
Limits: A phase 2 safety-and-futility trial that asked whether a larger trial was worth running, in people already diagnosed and not yet on medication, so it says nothing about preventing the disease.
ClinicalTrials.gov (U.S. National Library of Medicine). Study in Parkinson Disease of Exercise Phase 3 Clinical Trial: SPARX3. ClinicalTrials.gov, July 10, 2026.Regulatory noticeRead
What it found: Registry record, last updated July 10, 2026: SPARX3 (Northwestern University, with the University of Pittsburgh and the Parkinson Study Group) is active, not recruiting, with 370 enrolled since August 30, 2021, an estimated primary completion of July 31, 2027, and a primary outcome of change in MDS-UPDRS Part III motor score at 12 months.
Limits: A registry listing, not results, so it shows the trial exists and when it is expected to finish, not whether exercise helped.
U.S. Environmental Protection Agency. Risk Management for Trichloroethylene (TCE). U.S. Environmental Protection Agency, October 22, 2026.Regulatory noticeRead
What it found: EPA page last updated October 22, 2026: EPA issued a final TCE rule in December 2024; on October 14, 2026 it proposed moving the compliance date for several uses from December 18, 2026 to December 31, 2027, and says the TCE ban stays in place with interim workplace protections continuing. The page does not mention Parkinson's disease.
Limits: A regulatory status page that shows what the rule requires and when, not whether TCE causes Parkinson's disease, and the proposed dates are not final.
Patrick RP. Role of phosphatidylcholine-DHA in preventing APOE4-associated Alzheimer's disease. FASEB Journal. 2019;33(2):1554-1564.ReviewPubMed 30289748 · DOI
What it found: A single-author review that proposes APOE4 carriers have impaired brain uptake of free DHA but not of DHA bound to a phospholipid (DHA-lysoPC), and that phospholipid-bound DHA could raise plasma DHA-lysoPC and lower Alzheimer's risk. It reports no participants or data.
Limits: A hypothesis paper, so it tests nothing in people, and I found no trial showing that the proposal lowers Alzheimer's risk.
Rogan J, Patrick R. Joe Rogan Experience #1054 - Dr. Rhonda Patrick. FoundMyFitness (show notes for The Joe Rogan Experience), December 21, 2017.PodcastListen
What it found: Show notes for Rhonda Patrick's seventh appearance on the Joe Rogan Experience: at 00:04:20 and 00:04:35 the notes say fish roe and krill oil are rich in phospholipid DHA and that it enters the brain more readily than triglyceride DHA, and at 00:06:00 that the phospholipid form may be beneficial for people with APOE-related Alzheimer's disease.
Limits: I read the show notes, not the audio, and they describe a proposed mechanism rather than a trial result.
Patrick R. Aliquot #82: Reducing Alzheimer's Risk for APOE4 Carriers. FoundMyFitness, March 23, 2023.PodcastListen
What it found: A members-only FoundMyFitness episode hosted by Rhonda Patrick. The public page says APOE is a lipid-transport protein, that APOE4 is the main genetic risk factor for Alzheimer's, and that lifestyle factors may temper that risk, with seven listed topics: exercise, diet, ketogenic diets, education, sleep, alcohol, and air pollution.
Limits: The audio is for premium members, so I read only the public summary and topic outline and cannot say what she concludes on any of them.
Patrick R, Laukkanen J. #037 Dr. Jari Laukkanen on Sauna Use for the Prevention of Cardiovascular & Alzheimer's Disease. FoundMyFitness, June 15, 2017.PodcastListen
What it found: Rhonda Patrick interviews Jari Laukkanen, lead author of the Finnish sauna cohort papers, about sauna and cardiovascular and Alzheimer's risk; the show notes mention heart rate rising to 150 beats per minute and a chapter on adding cold-water immersion to the sauna.
Limits: I read only the show-note entry in the publisher's feed, not a transcript, so I cannot say what either speaker said about doses beyond the topics listed.
Patrick R. Dr. Rhonda Patrick: Maximizing Healthspan with Exercise, Sauna, & Cold Exposure. FoundMyFitness (YouTube), January 22, 2026.VideoWatch
What it found: A talk by Rhonda Patrick, followed by audience questions, covering exercise, sauna, and cold exposure; in it she gives the sauna and cold doses she bases on studies and says what she uses herself (about 180°F for sauna, about 50°F for 2 minutes for cold).
Limits: I read an auto-generated transcript on a third-party mirror (rosetta.to), because the YouTube page itself would not load for me; the title and channel were confirmed through YouTube's oEmbed, the date comes from the mirror, and the transcript was cut off partway through the Q&A. Title, channel, and the January 22, 2026 date were confirmed on YouTube; the figures quoted come from an auto-generated transcript.
Attia P, Patrick R. #252 ‒ Latest insights on Alzheimer's disease, cancer, exercise, nutrition, and fasting | Rhonda Patrick, Ph.D. The Peter Attia Drive, May 1, 2023.PodcastListen
What it found: Peter Attia's second conversation with Rhonda Patrick; the show notes include a segment on possible brain benefits of sauna and her personal protocol at 1:09:30.
Limits: The detailed show notes are behind a membership paywall, so I confirmed the topic but not what she said.
Budoff M, Manubolu VS, Kinninger A, Norwitz NG, Feldman D, Wood TR, et al. Carbohydrate Restriction-Induced Elevations in LDL-Cholesterol and Atherosclerosis: The KETO Trial. JACC: Advances. 2024;3(8):101109.Cohort studyPubMed 39372369 · DOI
What it found: Eighty people on a ketogenic diet for a mean 4.7 years with LDL-C of 190 mg/dL or higher (mean 272), HDL-C of 60 or higher, and triglycerides of 80 or lower were matched 1:1 to controls with mean LDL-C of 123 mg/dL. Coronary calcium was median 0 versus 1 (P=0.520), total plaque score was not different (P=0.357), and LDL-C did not track with plaque in either group.
Limits: Eighty matched pairs selected for a high-HDL, low-triglyceride profile, one time point, controls drawn from a different cohort, and plaque is not the same as heart attacks, so it cannot show long-term safety or apply to people with other lipid profiles.
Ference BA, Ginsberg HN, Graham I, Ray KK, Packard CJ, Bruckert E, et al. Low-density lipoproteins cause atherosclerotic cardiovascular disease. 1. Evidence from genetic, epidemiologic, and clinical studies. A consensus statement from the European Atherosclerosis Society Consensus Panel. European Heart Journal. 2017;38(32):2459-2472.Position standPubMed 28444290 · DOI
What it found: Consensus review of genetic studies, more than 200 prospective cohorts, Mendelian randomization studies, and randomized trials covering more than 2 million participants, over 20 million person-years, and over 150,000 cardiovascular events. It found a consistent, dose-dependent, log-linear link between LDL exposure and cardiovascular risk that grows with the duration of exposure, and concluded that LDL causes atherosclerotic cardiovascular disease.
Limits: A consensus review of other studies, not a new trial; it rests on the quality of the underlying genetic, cohort, and trial data.
Avgerinos KI, Spyrou N, Bougioukas KI, Kapogiannis D. Effects of creatine supplementation on cognitive function of healthy individuals: A systematic review of randomized controlled trials. Experimental Gerontology. 2018;108:166-173.Systematic reviewPubMed 29704637 · DOI
What it found: Systematic review of 6 randomized trials with 281 healthy people. Short-term memory and intelligence or reasoning may improve; long-term memory, spatial memory, attention, executive function, and reaction time were conflicting; young people showed no change and vegetarians responded better than meat-eaters.
Limits: Few, small, and varied trials, and the abstract reports no effect sizes or doses.