Regular physical activity and getting the recommended amount of sleep may reduce dementia risk later in life, according to a study by Akinkunle Oye-Somefun and colleagues, published in the open-access journal PLOS One.

An estimated 55 million people live with dementia worldwide, and both its prevalence and cost are expected to increase, with global costs projected to reach $2 trillion dollars by 2030. Current treatments for preventing or treating dementia have limited efficacy; therefore, public health efforts have also aimed at healthy lifestyle factors to reduce the risk of dementia before symptoms occur. Healthy behaviors such as regular physical activity and good sleep hygiene are known to support cognitive health; however, there remains a need to better understand their relationship to dementia.

In this systematic review and meta-analysis, researchers analyzed data from 69 prospective cohort studies representing millions of community-dwelling adults aged 35+, to see if there was a link between the development of dementia and three lifestyle behaviors: physical activity, sedentary behavior, and sleep duration. Each of the observational studies recorded behaviors of cognitively healthy participants, then followed up at a later timepoint to report subsequent rates of dementia.

Overall, the meta-analysis found that regular physical activity, less sedentary time, and appropriate nightly sleep (7–8 h) were associated with a lower subsequent risk of dementia. Regular physical activity was associated with an average 25% lower risk of dementia among the 49 studies analyzed; however, the researchers note that there was considerable heterogeneity between the studies.

Too little sleep (<7 h) or too much sleep (>8 h) was associated with an 18% and 28% higher subsequent risk of dementia, respectively, compared to optimal nightly sleep of 7-8 hours, though there was again considerable heterogeneity among the 17 studies analyzed. Prolonged sitting (>8 hours per day) was associated with a 27% higher risk of dementia among the 3 relevant studies analyzed.

The study is consistent with and expands on previous research, using a large, diverse population with long follow-up times. While the study design cannot show any causative link between physical activity, sleep and dementia, the findings suggest an association between adherence to recommended physical activity and sleep levels in middle- and older-age adults and lowered dementia risk later in life.

The authors add: “Dementia develops over decades, and our findings suggest that everyday behaviours such as physical activity, time spent sitting, and sleep duration may be linked to dementia risk. Understanding how each of these behaviours relates to risk over time may help researchers identify opportunities to support brain health across the life course.”

“Separately, one aspect I personally found most interesting while conducting the study was the relatively limited evidence base on sedentary behaviour. Despite growing recognition that prolonged sitting is distinct from physical inactivity, we found only a small number of cohort studies examining its relationship with dementia risk. This highlights an important gap for future research.”

Exercise may reduce symptoms of depression to a similar extent as psychological therapy, according to an updated Cochrane review. When compared with antidepressant medication, exercise also showed a similar effect, but the evidence was of low certainty.  

Depression is a leading cause of ill health and disability, affecting over 280 million people worldwide. Exercise is low-cost, widely available, and comes with additional health benefits, making it an attractive option for patients and healthcare providers. 

The review, conducted by researchers from the University of Lancashire, examined 73 randomized controlled trials including nearly 5,000 adults with depression. The studies compared exercise with no treatment or control interventions, as well as with psychological therapies and antidepressant medications. 

The results show that exercising can have a moderate benefit on reducing depressive symptoms, compared with no treatment or a control intervention. When compared with psychological therapy, exercise had a similar effect on depressive symptoms, based on moderate-certainty evidence from ten trials. Comparisons with antidepressant medication also suggested a similar effect, but the evidence is limited and of low certainty. Long-term effects are unclear as few studies followed participants after treatment.  

Side effects were rare, including occasional musculoskeletal injuries for those exercising and typical medication-related effects for those taking antidepressants, such as fatigue and gastrointestinal problems.

“Our findings suggest that exercise appears to be a safe and accessible option for helping to manage symptoms of depression,” said Professor Andrew Clegg, lead author of the review. “This suggests that exercise works well for some people, but not for everyone, and finding approaches that individuals are willing and able to maintain is important.” 

The review found that light to moderate intensity exercise may be more beneficial than vigorous exercise, and that completing between 13 and 36 exercise sessions was associated with greater improvements in depressive symptoms.

No single type of exercise was clearly superior, although mixed exercise programmes and resistance training appeared more effective than aerobic exercise alone. Some forms of exercise, such as yoga, qigong and stretching, were not included in the analysis and represent areas for future research. Long-term effects are unclear as few studies followed participants after treatment.

This update adds 35 new trials to previous versions published in 2008 and 2013. Despite the additional evidence, the overall conclusions remain largely unchanged. This is because the majority of trials were small, with fewer than 100 participants, making it difficult to draw firm conclusions.

“Although we’ve added more trials in this update, the findings are similar,” said Professor Clegg. “Exercise can help people with depression, but if we want to find which types work best, for who and whether the benefits last over time, we still need larger, high-quality studies. One large, well-conducted trial is much better than numerous poor quality small trials with limited numbers of participants in each.”

Aerobic exercise, such as running, swimming, and dancing, may be most effective for relieving the symptoms of depression and anxiety, finds an overarching (umbrella) review and data synthesis of the available evidence, published in the British Journal of Sports Medicine.

While supervised and group exercise may be best for reducing depression, shorter (up to 8 weeks) lower intensity exercise may be best for relieving anxiety.

But all forms of exercise are as good as, or better than, medication and talking therapies, regardless of age or sex, the findings indicate.

Depression and anxiety affect up to 1 in 4 people worldwide, with the highest prevalence among young people and women, note the researchers. And previously published research suggests that exercise compares favourably with psychotherapy and medication for easing the symptoms, they add.

But it’s not clear how well exercise might work at different ages, frequency, and intensities.And previous overarching syntheses have focused only on adults or included participants with potentially influential factors, such as long term conditions.

The researchers therefore set out to comprehensively estimate the impact of exercise on depression and anxiety symptoms across all age ranges, including in those with and without a clinical diagnosis; and to find out whether the type, length, frequency, intensity, and supervision of exercise, and individual or group participation might influence outcomes.

They scoured research databases for pooled data analyses of randomised controlled trials that compared exercise with either another type of activity, or a placebo, or no active intervention, and published in English up to July 2025.

Eligibility criteria included planned, structured, repetitive and purposeful physical activities to improve physical and mental health; and all forms, intensities, frequencies and settings (individual or group) of exercise.

For depression, 57 pooled data analyses, comprising 800 component studies, involving 57,930 participants aged between 10 and 90, were included in the overarching synthesis.

These participants had been diagnosed with clinical depression or were experiencing depressive symptoms, but had no other co-existing conditions. Exercise interventions were categorised as aerobic (19 pooled data analyses); resistance, such as strength training (8); mind–body, such as yoga, tai-chi, and qigong (16); or a mix (39).

For anxiety, 24 pooled data analyses, comprising 258 component studies, involving 19,368 participants, aged between 18 and 67, were included in the overarching synthesis. Exercise interventions were categorised as aerobic (7); resistance (1); mind–body (9); or mixed (13).

Synthesis of the pooled data analyses showed that exercise had a medium sized effect on depression symptoms and a small to medium sized effect on anxiety symptoms, with the most substantial effects found for young adults (18-30) and women who had recently given birth.

All forms of exercise were associated with positive effects, with aerobic, group based and supervised formats the most effective for relieving depression symptoms. Aerobic, resistance, mind–body and a mix of different exercise formats had a medium sized impact on the relief of anxiety symptoms.

The effects were on a par with, or better than, medication or talking therapies.

The researchers acknowledge some limitations to their findings. These include the variable interpretations of exercise intensity and length among the pooled data analyses, and the relative paucity of pooled data analyses on the impact of exercise across the lifespan.

But they nevertheless conclude: “This meta-meta-analysis provides robust evidence that exercise effectively reduced depression and anxiety symptoms across all age groups, comparable with, or exceeding, traditional pharmacological or psychological interventions.

“Group and supervised formats gave the most substantial benefits, underscoring the importance of social factors in mental health interventions. With evidence that different characteristics of exercise appear to impact depression and anxiety at varying magnitudes, tailored exercise programmes must be prescribed.”

They continue: “Given the cost effectiveness, accessibility, and additional physical health benefits of exercise, these results underscore the potential for exercise as a first line intervention, particularly in settings where traditional mental health treatments may be less accessible or acceptable.”