Does Better Fitness Protect Us From Dementia And Depression?

I'm not a mental health expert. I only know that I always feel better after I run, cycle or do any other form of exercise. Especially if I've been particularly stressed about something or everything.

We know for sure that having good cardiorespiratory fitness is a strong indicator of overall physical  health. However, is someone with good cardiorespiratory fitness less likely to have mental health disorders or dementia later in life?

A newly published systematic review and meta-analysis provides new updates on this link across all age groups in their study (Diaz-Goni et al, 2026). 22 studies (out of 27 chosen) with 4,007,638 participants were studied in that review. 

The participants were between 18 and 64 years old, who had fitness measured at baseline and followed for 4 to 29 years. Different methods were used for measuring fitness. Some studies used VO2 max, others used indirect or submaximal exercise tests while others measured peak workload and exercise duration. Note that this paper talks about cardiorespiratory fitness and NOT about VO2 max values.

Higher cardiorespiratory fitness was associated with substantially lower future risk of depression, psychotic disorders and dementia. However it did not show to clearly help with anxiety.

Each 3.5 mL/kg/ min (or 1 MET) increase in cardiorespiratory fitness was associated with a 5 percent lower risk of depression and 19 percent lower risk of dementia.

Overall, those with higher cardiorespiratory fitness had a 36 percent lower risk of depression, 39 percent lower risk of dementia and 29 percent lower risk of psychotic disorders compared to those with lower fitness.

The authors discussed a few potential mechanisms that may explain why higher cardiorespiratory fitness helps mental or neurocognitive disorders.

From a physiological perspective, improved brain blood flow, vascular function induces structural, cellular and molecular adaptations to enhance neuroplasticity which then support cognitive and emotional regulation.

Exercise and higher cardiorespiratory fitness has been shown to help maintain the size/ volume of the hippocampus. The role of the hippocampus is linked to emotion regulation, memory and cognitive resilience. Atrophy of the hippocampus has been consistently linked to mental and cognitive disorders.

Mental health disorders and neurodegeneration are definitely complex and multifactorial. Please note that the authors also did not just conclude that "exercise is the answer". They concluded that higher cardiorespiratory fitness appears to be associated with a lower risk of several mental and neurocognitive disorders and cardiorespiratory fitness may be a useful marker to sort out groups at risk.

This is also interesting to note. Because only 1 or 2 studies were available, the authors were not able to study them as a group. Those individual studies suggested that higher fitness may be associated with lower risk of bipolar related disorders, dissociative, obsessive-compulsive and stressor-related disorders, sleep apnea as well as anxiety and ADHD in children. Depression in girls also appeared lower with higher fitness.

If the fitness influencers do pick up on this topic, I hope they do not simplify it by making it as easy as doing "some exercise or sports". 

So taken at face value, higher cardiorespiratory fitness seems to lower risk across a wide range of psychiatric and neurocognitive disorders. Do note that genetic predisposition, chronic pain, social support, smoking and diet are definitely confounding factors.

The evidence does continue to add up showing that higher cardiorespiratory fitness helps with physical disease and premature death, but also with better mental health, lower dementia risk and other mental disorders. 

Reference

Diaz-Goni V, Lopez-Gil JF, Rodriguez-Gutierrez E et al (2026). Cardiorespiratory Fitness And Risk Of Mental Disorders And Dementia: A Systematic Review And Meta-Analysis. Nat Mental Health. DOI: 10.1038/s44220-026-00599-4

Girls Get A Lot More Anxious Than Boys

Picture from Motherwellmag

In a first of its kind study, Prof Setoh and colleagues from Nanyang Technological University found that girls are a lot more anxious than boys. This happens between the ages of 8.5 and 13 years when they go through a sharp spike in social anxiety. They fear being judged negatively in social situations.

By the time they turn 13, their social anxiety levels are significantly higher than boys. If untreated, this may lead to poor mental health and interpersonal relationships. Academic and work performance later in life may be affected as well.

The article was just published on 300825 in the Research On Child And Adolescent Psychopathology. The Straits Times also published an article on it on 010925.

ST 010725

You must be wondering why I chose this topic this week, or wondering about my credentials on adolescent mental health. 

Just after I came across the newspaper article, I remembered a recent study by Lundgren et al  (2025) on how physical activity during certain periods can protect children from developing depression, anxiety and addiction. Their study was based on a large group of Swedish children followed from birth until their 18th birthdays. The long time frame allowed comparison between parent-rated levels of activity to diagnoses from a national registry. This is to eliminate pre existing issues that caused low activity levels or transient dips that were interpreted as social anxiety issues.

The study involved 17,055 children, who were born between 1997-1999. The parents had to rate various aspects of their child's health at 5, 8 and 11 years. Activity levels were tracked separately for school days and non school days. Participation in organized sports were tracked at 11 years and reported in hours per week.

The authors found that physical activity (reported by parents) declined from 4.2 to 2.5 hours each day between 5 and 11 years of age. Analyses showed that boys and girls had different outcomes and patterns. 

Time outdoors showed no protective associations while participation in organized sports at 11 years of age showed significant protective effects on anxiety and addiction for both boys and girls and on depression for boys. The authors concluded that his study provides evidence that physical activity and participation in organized sports may have protective effects against several adolescent mental health diseases.

Possibly policymakers working to control vaping in Singapore could use this information?

Access to the articles at the links below.

References

Lundgren O, Tigerstrand H, Lebena A et al (2025)Impact Of Physical Activity On The Incidence Of Psychiatric Conditions During Childhood: A longitudinal Swedish Birth Cohort Study. BJSM. 1:59(14): 1001-1009. DOI: 10.1136/bjsports-2024-108148

Tng GY, Law ECChen HY et al (2025). Developmental Trajectories Of AnxietySubtypes From ChildTo Early Adolescence: The Role Of Parenting practices And Maternal Distress. Res Ch Adoles Pysch. DOI: 10.1007/s10802-025-01364-4 

Are You A Weekend Warrior?

Picure from DetailingWiki

My patient and his wife were asking me about my exercise routine and they were surprised when I told them that I still exercise 6 days a week, with one total rest day. 

I'm guessing they do not know about my training routine when I was still competing. They were saying that they found it really difficult to exercise during the weekdays. They ususally only found time on the weekend to exercise.

I told them to fret not as fitting in their exercise on weekends will still reap significant health and survival benefits as well as help their brain health.

Findings from an earlier large study (64,000 subjects) showed that people who pack all of their exercise into 1 or 2 days of the week (often referred to as weekend warriors) appear to lower their risk of dying about as much as people who exercised 3 times a week or more (O' Donovan et al, 2017).

Another recent study (August 2024) showed that a weekend warrior who met physical activity guidelines had similarly lower risks of dementia, stroke, Parkinson's disease, depressive disorders and anxiety compared to a more regular activity pattern (Min et al, 2024). Physical activity guidelines are mor than 150 minutes of moderate intensity exercise per week. 

This study by Min et al (2024) included 75, 629 participants. Their findings highlight that this is an alternative for those who are unable to exercise more regularly during the week days. 

Go and be active whenever you can

For those of you are are struggling to fit in any exercise during the week, remember that any activity is worthwhile, even if it is just on the weekend.

References

Min J, Cao Z, Duan T et al (2024). Accelerometer-Derived "Weekend Warrior" Physical Activity pattern And Brain Health. Nat Aging. 4: 1394-1402. DOI: 10.1038/s43587-024-00688-y

O' Donovan G, Lee I, Hamer M et al (2017).Association Of "Weekend Warrior" And Other Time Physical Activity Patterns With Risks For All-cause, Cardiovascular Disease, And Cancer Mortality. JAMA Int Med.177(3): 335-342. DOI: 10.1001/jamainternmed.2016.8014

Does Eating Fried Food Make You Anxious Or Depressed?

I have a weakness for french fries, I can eat them for all my meals and not get sick of it. Hence, I was not happy when I read that high fried food consumption (particularly potatoes) can affect your mental health.

This recently published study studied data on depression, eating patterns and anxiety levels on eating patterns of 140,278 people collected over 11 years. Subjects diagnosed with depression in the first 2 years were excluded. Follwing that, the researchers found 8,294 cases of anxiety and 12,735 cases of depression in people who ate fried food.

All in all, the researchers found that people who regularly ate fried food (particularly fried potatoes like french fries) were 12 percent more likely to be anxious and 7 percent higher risk of depression compared to those who did not eat fried food. Those who ate fried potatoes had a 2 percent higher risk of depression than those who eat fried chicken (white meat). The associations were more pronounced among male and younger consumers.

The researchers suggested that a chemical called acrylamide formed during frying is responsible for the higher risk of depression and anxiety. This affects the brain lipid (fat) metabolism and affects permeabilty of the blood brain barrier inducing stress mediated neuro (brain) inflammation. 

An earlier study on 715 Japanese workers (Yoshikawa et al, 2016) also found that there was a "significant positive indirect association" between eating fried food and experiencing depression. The Japanese authors concluded that "frequency of fried food consumption was associated with lower resilience to depression".

I need to point out that the researchers did not prove that eating fried food actually caused anxiety and depression. They merely found a link between eating fried food and an increased risk of anxiety and depression.

The researchers also did not determine whether people were more likely to become anxious and depressed from eating fried food or because they ate fried food when they were feeling down. We all know that fried food is comfort food for many people. People who are feeling anxious or depressed may turn to fried food for comfort.

People who are feeling down and depressed may also have less energy to prepare their own meals. They may then resort to easy and fast (fried) food as do people with overwhelmingly busy schedules. High trans fat in fast food is linked to inflammation leading to mood disorders. Being low in nutrients, fried food also contributes to poor overall diet quality.

So, are we supposed to consume less fried food? Eating too much fried food affects your gut (stomach) microbiome and when your gut does not feel great, it affects your physically and emotionally. 

We definitely need more research to look at how food, weight, diet, mood and other factors interact and affect us. For now, I will continue to eat french fries, but in much smaller amounts.

References

Wang A, Wan X, Zhuang P et el (2023). High Fried Food Consumption Impacts Anxiety And Depression Due To Lipid Metabolism Disturbance And Neuroinflammation. PNAS. 120(18) e2221097120. DOI: 10.1073/pnas.2221097120.

Yoshikawa E, Nishi D and Matsuoka YJ (2016). Association Between Frequency Of Fried Food Consumption And Resilience To Depression In Japanese Company Workers: A Cross-sectional Study. Lipids Health Dis. 15:156. DOI: 10.1186/s12944-016-0331-3.

Another Call For Bike Lanes In Singapore

ST 280820

After my previous article written earlier this month, it is heartening to see transport minister Ong Ye Kung suggest that certain under-used road lanes be converted to cycling and bus lanes in today's Straits Times (page A4 under Top of the news).

Well, definitely preferably cycling lanes please.

Remember Prime Minister Lee Hsien Loong's 2017 National Day Rally speech on the number of Singapore citizens with diabetes?  I suggested weight training as evidence suggests it helps with improved insulin sensitivity among people with diabetes and pre diabetes. If more Singaporeans start to cycle to run errands or work instead of taking the car, that definitely adds up too.

By riding to work, you get a workforce that gets fitter as they lose weight, save money and help the environment. Our mental health improves and we feel less stress and feel happier. In addition to having a cleaner and greener Singapore, we reduce our carbon footprint as well.

I have a particular favorite, when you ride bikes, you get the sheer joy of feeling the wind in your face - a better and greener version than driving a convertible.

Over to you Minister Ong Ye Kung and the Ministry of Transport.

Exercise As A Remedy For COVID Stress

Today is the last day of the circuit breaker (CB) or lockdown period in Singapore. Finally, light at the end of the tunnel.

During the CB, I've noticed a lot more people in my neighborhood running than before, and many you can tell, never really exercised regularly previously. But good for them, at least they are exercising now. I guess with all the free time, gyms closed and not wanting to lose their sanity, many people go walking and running.

You can probably guess that quarantines and lockdowns or similar measures to combat plagues are associated with poor mental health. Past quarantines resulted in lingering stress levels, confusion and mounting anger (Brooks et al, 2020).

A recently published study (though not peer reviewed) done in the early stages of the lockdown (in USA) suggested that benefits of exercising extended beyond just physical benefits and help us mentally too (McDowell et al, 2020).

The study found that people who managed to keep exercising during the lockdown were less depressed and more mentally resilient compared to those whose activity levels declined.

Data from manufacturers of activity trackers showed that most people's daily step count decreased from March since most countries were under lockdown during that period.

In that study, researchers asked about 3000 non smoking subjects probing questions about their personal lives. Multiple questionnaires about how often they exercised and how many hours were spent sitting before the pandemic began.

This was compared to the lockdown period in April. Subjects were asked if they were fully self quarantined at home or did they get a chance to go outside while following social distancing rules.

They were also asked about their current mental health, whether they had symptoms of depression, anxiety, loneliness or if they were generally happy.

After collating the replies, the researches split the subjects into groups based on whether they previously had or had not met the standard exercise guidelines of 150 minutes per week of moderate exercise now compared to before the lockdown. The researchers then compared exercise routines and moods.

No surprises that the researchers found that those who managed to exercise were more cheerful and vice versa. The people  who previously had been active but because of the lockdown rarely exercised were more likely to be depressed, anxious, lonely and worried compared those who still managed get in 150 minutes of exercise a week.

Those subjects in full quarantine were the most affected as few managed to maintain any exercise routine and they reported feeling sad, depressed and solitary.

After looking at the study in detail, I noticed that most of the respondents were middle class well educated whites. Not many of other races were represented.

Because this study relied on their memories of the exercise routines, the findings may not be totally reliable as it covers separate but temporary parts of their lives during the lockdown. We can perhaps infer that exercise and their moods were linked.

I can definitely testify that exercise can improve moods and well being. If you haven't been able to exercise and get out much during the CB, bear in mind that we still have to exit the CB in stages.

Stay safe.


References

Brooks SK, Webster RK et al (20120). The Psychological Impact Of Quarantine And How To Reduce It: Rapid Review Of The Evidence. 395: 912-920. DOI: 10.1016/S0140-6736(20)30460.

McDowell C, Lansing J et al (2020). Changes In Physical Activity And Sedentary Behaviour Due To COVID-19 Outbreak And Associations With Mental Health in 3,052 Adults. Cambridge Open Engage. DOI:10.33774/coe-2020-h0b8g.

See if you can guess where I took the following pictures during my solo CB rides.

Guess where this tank is?

Abandoned guard tower

Not in use water tank?

Sleepless In Singapore

The 3 amigos

My wife and both two boys recently started wearing an activity tracker. The boys have been very diligent regarding logging 10,000 steps daily. They would even pace up and down the room or hallway just to get more steps to meet this goal.

Actually, I'm much more interested in tracking how much they sleep since it is a well know fact that Singaporeans do not get enough sleep. In fact, a survey showed that 41 percent of Singapore adults get between 4 to 6 hours of sleep a night even though they should be clocking in 7 to 8 hours.

That is bad news as shown by neuroscience Professor Michael Walker in his 2017 New York Times bestseller Why We Sleep. More than 20 large scale epidemiological studies tracking millions of people over many decades showed that "the shorter your sleep, the shorter your life".

In fact Professor Walker suggested that "leading causes of disease and death in developed nations - cue disease, obesity, dementia, diabetes and cancer - all have causal links to a lack of sleep".

The cost to mental health is significant too. Sleep problems may increase risk for developing certain mental illnesses like depression and anxiety disorders, as well as result from them.

Back to kids. It is difficult enough raising a child, but when a child is a student athlete, another layer is added.

My boys and their trackers

I would suggest all student athletes eat five good meals/ snacks a day. This is to help fuel the child's body for long school days. From the time they leave home between 6-7 am in the morning to lessons ending at around 2 pm but most likely extended for training, competitions and tuition.

Think of it like a car. Your student athlete is the car and you need to have good fuel in the car. Parents and child can work together to plan meals based on the student's weekly schedule.

Sleep is the best way for your child's body to recover. It trumps all the compression garments, recovery food, sports drinks etc. With enough sleep there is less chances of your child falling sick and getting injured.

Quality sleep is better than long hours, but good to have both. And it's best to rest without distractions like a mobile phone buzzing through out the night. Also be wary that an activity tracker may overestimate total sleep time (Lee et al, 2019).

One of my patient's child used to be a elite junior triathlete. She would keep the child's phone at bedtime as her child would be using the phone and not sleeping if she didn't.

Conversing with your child athlete while having healthy sit down meals as a family (without your phones) will help touch on many of these points.

Good nutrition, regular, early sleep schedule and physical activity as a family.  Make that your priority in the new year.


Reference

XK Lee, Chee NIYN, JL Ong et al (2019). Validation Of a Consumer Sleep Wearable Device With Actigraphy And Polysomnography In Adolescents Across Sleep Opportunity Manipulations. K Clin Sleep Med. 15(9): 1337-1346.

The above article is done by Singapore researchers at the Centre for Cognitive Neuroscience, under the Duke-NUS Medical School.

I love this picture I took from a book - Goodnight Darth Vader which I bought for my son by Jeffrey Brown.

How Healthy Are Elite Athletes?

Taken with my iPhone off my computer from Cyclingnews.com

Compared to most people in the general population yes, elite athletes are very healthy if you read the article by Lemez et al (2015). However, this is a controversial topic that has been debated for years by athletes themselves, coaches and researchers.

I'm sure you've watched the riders at the Tour De France or the athletes competing at the Olympics. At these competitions, they usually rested and focused, look lean, powerful, slick and bursting with energy.

Can you guess how much it took for them to get there? All the grueling training and obsessive dedication required to reach those levels. Is at good for them? Will that pursuit of sustained excellence damage their health?

The answer depends on how you define health and who you compare elite athletes to.The findings from the comprehensive review on mortality and longevity in elite athletes is very clear. Elite athletes fare better than everyone else when it comes to longevity and disease if you define health as "the absence of disease and the capacity to enjoy life and withstand challenges."

That article by Lemaz et al (2015) examined more than 450, 000 athletes and found that elite athletes live four to eight years longer when compared to an equally matched control group in the general population.

Athletes who competed in running, cycling, soccer and swimming (sports with high aerobic demands) had the greatest benefits. Those athletes have lower rates of heart disease, stroke and smoke related cancers. The Tour de France cyclists for example have a 40 percent lower mortality rate than non athletes.

See how skinny he is (taken from Cyclingnews.com)

The other element of health is psychological, the question of enjoyment in life. That is difficult to quantify and answer.

Some studies show that elite athletes have better mental health after their retirement from elite sports. This may be due to the resilience they developed while competing or that exercise itself (trumps medication when treating depression).

However, other studies show comparable rates or even potentially increased risk for mental health issues. This is actually also dependent on the support the elite athletes received during their athletic career and early retirement (Rice et al, 2016).

Similar to an overworked doctor in the emergency department, corporate lawyer or investment banker, elite athletes often put into situations that require them to sacrifice a lot for their mind and body.

The best endurance athletes will push their bodies and their minds as far as humanly possible and this may not be good for them. If not controlled, that very same drive and determination that propels the elite athlete can eventually become harmful.


References

Lemez S, Baker J et al (2015). DO Elite Athletes Live Longer? A Systematic Review Of Mortality And Longevity In Elite Athletes. Sports Med Open. DOI: 10.1186/s40798-015-0024-x.

Rice SM, Purcell R et al (2016). The Mental Health Of Elite Athletes: A Narrative Systematic Review. Sports Med. 46(9): 1333-1353. DOI: 10.1007/s40279-016-0492-2.