Exercise cuts dementia risk by 45%

 From News Medical/Life Sciences

In a recent study published in JAMA Network Open, researchers examined whether physical activity during early adulthood, midlife, or late life is most strongly associated with a reduced risk of developing Alzheimer’s disease or all-cause dementia.

Their findings indicate that higher physical activity in midlife and late life was linked to a 41-45% lower risk of all-cause dementia, with slightly stronger reductions observed in the highest activity quintile (Q5), and similar patterns were observed for Alzheimer’s disease.

Lifestyle and Timing Challenges in Dementia Prevention Research

Dementia poses a major global health challenge, and effective preventive strategies are urgently needed because current drug treatments for Alzheimer’s disease offer only modest benefits, are costly, and may cause side effects. Growing evidence suggests that modifying lifestyle factors could prevent a substantial portion of dementia cases.

Physical activity is among these modifiable factors, especially during midlife. However, it remains unclear when across adulthood physical activity matters most for long-term brain health. Past research has shown that being physically active in midlife or later life is associated with better brain structure, improved cognitive performance, and a lower risk of dementia. 

Physical activity earlier in life may also be beneficial. However, many studies rely on older adults recalling their youthful activity levels, which introduces error and the possibility of reverse causation, especially when cognitive impairment is already present. As a result, the specific life stages at which physical activity has the greatest impact remain uncertain. 

To clarify this issue, researchers used long-term, prospectively collected data from the Framingham Heart Study, which began in the early 1970s. They aimed to determine whether physical activity in early adulthood, midlife, or late life is most strongly linked with reduced dementia risk.

Participant Selection Across Early, Midlife, and Late-Life Stages

Participants were included if they were dementia-free and had physical activity data at a baseline exam corresponding to one of three life stages: early adulthood (ages 26 to 44), midlife (ages 45 to 64), or late life (ages 65 to 88).

The final analytic samples included 1526 early adult, 1943 midlife, and 885 late life participants. All participants provided informed consent, and the study followed established guidelines.

Physical Activity Measurement Using the Activity Index

Physical activity was measured using the Physical Activity Index, which assigns weighted values to hours spent in sleep, sedentary, slight, moderate, and heavy activities. Higher scores indicate greater total activity. Scores were divided into age-specific quintiles for comparison.

Participants were followed until dementia diagnosis, death, or December 31, 2023. Dementia, all-cause or Alzheimer’s disease, was diagnosed through expert consensus using standard diagnostic criteria.

Cox proportional hazards models estimated hazard ratios for dementia risk across physical activity quintiles, adjusting for age, sex, education, body mass index (BMI), smoking, hypertension, diabetes, hyperlipidemia, and apolipoprotein E (APOE) ε4 status.

Additional analyses considered tertiles and quartiles of activity, activity intensity levels, APOE ε4 stratification, and Alzheimer’s dementia specifically.

Dementia Incidence and Early Patterns Across Life Stages

Participants in late life generally had lower education, higher BMI, and more cardiometabolic conditions than younger groups. Throughout follow-up, 567 individuals developed dementia, 4 percent of early adult, 14 percent of midlife, and 26 percent of late life participants.

Across all age groups, participants with lower physical activity had higher mortality. These results emphasize the higher risk of dementia among less active individuals, especially in midlife and late life.

After accounting for demographic and health factors, only higher physical activity during midlife and late life, not early adulthood, was associated with a significantly reduced risk of all-cause dementia.

In both midlife and late life, individuals in the highest activity quintiles had a significantly lower dementia risk than those in the lowest quintile, approximately 40 percent lower, with Q4 and Q5 showing the strongest associations. 

Early adult activity showed no significant association with dementia risk, likely reflecting the small number of dementia cases in this age group.

APOE ε4 Genetics Modify Midlife and Late-Life Activity Effects

APOE ε4 status modified these associations. The interaction between APOE ε4 and physical activity was statistically significant for midlife only, indicating that genetic risk influenced the strength of the association during this period.

Among non-carriers, higher midlife activity was linked to substantially lower dementia risk, while late-life activity predicted reduced risk for both carriers and non-carriers. In ε4 carriers, only the highest late-life activity level, Q5, reached statistical significance. 

Patterns were similar for Alzheimer’s dementia specifically, with the highest level of midlife and late-life activity associated with lower incidence. However, for Alzheimer’s disease in ε4 carriers, the association did not reach statistical significance, a nuance not attributable to insufficient sample size in the late-life group.

Moderate and heavy midlife activity were particularly protective, whereas slight activity showed no benefit. In late life, benefit was observed regardless of activity intensity.

Strengths and Limitations of the Life-Course Physical Activity Approach

The study shows that midlife and late-life physical activity are key periods during which higher activity levels are associated with reduced risk of all-cause and Alzheimer’s dementia.

Midlife benefits were tied to moderate or heavy activity, whereas late-life benefits occurred regardless of intensity. APOE ε4 status influenced these associations, with stronger effects in non-carriers during midlife and more limited effects in carriers until late life.

These findings reinforce the importance of promoting physical activity across adulthood, particularly during midlife, to support cognitive health.

The life course design, extended follow-up, comprehensive adjudication of dementia, and detailed covariate data are significant strengths of this analysis. However, the predominantly European ancestry sample, limited numbers of dementia cases in early adulthood, reliance on self-reported activity at a single time point, inability to assess earlier-life activity, and potential misclassification or survival bias may limit the generalizability of the results.

Overall, the study identifies midlife and late life as critical windows for physical-activity-based dementia prevention.

Journal reference:

• Marino, F.R., Lyu, C., Li, Y. (2025). Physical Activity Over the Adult Life Course and Risk of Dementia in the Framingham Heart Study. JAMA Network Open 8(11), e2544439. DOI: 10.1001/jamanetworkopen.2025.44439, https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2841638

The rat about to destroy civilisation

 By Pedro Molina

The 100-hour battery is real

Intra-day storage — soaking up solar at the middle of the day to be released in the evening and overnight — is perfectly feasible using lithium-ion or sodium-ion batteries, which are getting cheaper and cheaper.  But what happens when there are prolonged spells where there is little solar, no wind, and high demand because it's cold, what the Germans have dubbed dunkelflaute (doonkel-flowta)?  For that we need long-duration storage, which I've talked about before.

One of the options for long-duration storage is the iron-air battery.  And it's now in commercial production in the US.  The video below from Just Have A Think discusses it.

Wind and solar generate more than gas

 From Canary Media

It’s the first month [ever] [that] wind and solar [have] combined to produce more electricity than natural gas did, per new global data from energy think tank Ember.

Just five years ago, the gap between what those renewable resources and gas generated was huge. Even in the best month for renewables, gas plants churned out about twice as much power. Now, the picture is very different: Wind and solar generated about 532 terawatt-hours of electricity [+13.4% yoy] worldwide last month, while gas contributed just 477 TWh [-3.9%].  

This won’t be the first time wind and solar outcompete gas on the global stage.

Last year, the world met 75% of its new electricity demand with solar alone, and the remainder with other forms of carbon-free energy. The result? Fossil-fuel power generation declined — very slightly — even though the world consumed more electricity.

Meanwhile, the ongoing war in the Middle East bolsters the case for renewable energy. Iran’s blockade of the Strait of Hormuz and its retaliatory strikes on Qatar forced one-fifth of the global liquefied natural gas export capacity offline earlier this year, causing supply shortages and price spikes for the many countries that depend on imported, rather than domestic, natural gas.

Already, some nations appear to have increased their adoption of renewables to shore up their national energy security.

The caveats of the April milestone must be mentioned. It’s just one month — and occurred during the shoulder season, the best time of the year for renewables, as breezes pick up and days get sunnier [in the northern hemisphere, it's winter in the southern.  The seasonal cycles obvious in the data are because the northern hemisphere has more land and more people than the southern]

Then there’s King Coal, which still produces far more electricity worldwide than wind and solar. But it’s clear where we’re headed. The share of coal-fired electricity actually fell by half a percentage point from 2024 to 2025, marking the first annual drop since Covid and the first time in history that the dirty fuel produced less than a third of the world’s power. [Just as important: wind plus solar plus other renewables (mostly hydro) provided more electricity in April (925 TWh) than coal (758 TWh).]

In other words, coal should watch its back: It’s only a matter of time before wind and solar come for its crown, too.

Oz recession is prolly already happening

 I haven't updated my Australian coinciding and leading indices, because I haven't updated my data banks.  But fortunately, the Australian Industry Group (AIG) and S&P Global have updated their "PMIs", and in the past these have correlated quite well with my coinciding index. The charts are shown below.  Clearly this is in part a response to the Gulf War, but it is also being driven by the RBA's interest rate increases.  

A humungous El Niño is on the way

From Zack Labe

Sea surface temperatures are already surging to record high levels for this time of year in key El Niño monitoring areas.

This will prolly push global temperatures towards 1.7 degrees above pre-industrial (1850-1900) levels. This is releasing heat into the atmosphere already accumulated in the sea, so it doesn't change the underlying trajectory — though it may move some world climate systems past tipping points — but it will still deliver terrible heatwaves, droughts, bushfires and floods. And meanwhile the underlying temperature is continuing to rise, and its increase appears to have been accelerating.

AI plumber

 By Australian cartoonist Matt Golding