No Need To Cool Down After Exercise?

Athletes, coaches and physical education teachers have always been told that an active cool down is more effective for promoting post exercise recovery than a passive cool down (no activity). This is assumed to allow for individuals to perform better during subsequent training sessions or competition and perhaps even lower the risk of injury. 

However, there is not much research on whether the above is true. I've written previously how it may be unnecessary to cool down after exercise. What if I say that in some cases an active cool down may even be harmful?

The most widely used post recovery exercise intervention is probably the active cool down. It is commonly referred to as the 'warm down'. This is usually a 5 to 15 minutes of low to moderate intensity exercises after exercise/ competition. Some will do a slow jog, cyclists often ride easy on the bike while it's attached to a stationary trainer.

The following review by Van Hooren and Peake (2018) compares the effects of various types of active cool downs with passive cool downs on sports performance, injuries, long term adaptive responses and markers of post exercise recovery.

Ready for the summary? 

The review shows that an active cool down helps lead to faster removal of lactate in blood. However the practical relevance of this finding is questionable since lactate is not necessarily removed faster from muscles. 

An active cool down can partially prevent the depression of circulating immune cell counts after exercise, although it is unknown if this leads to fewer infections and illnesses.

An active cool down can definitely result in a faster recovery of the cardiovascular and respiratory system after exercise/ competition, but it remains unknown if this reduces post exercise fainting and cardiovascular complications.

Active cool downs does NOT significantly reduce delayed onset of muscle soreness (DOMs) or improve the recovery of indirect markers of muscle damage. It does not significantly alter the recovery of neuromuscular and contractile properties of muscles, it does not improve range of motion of muscles, and does not reduce musculotendinous stiffness following exercise. It may even interfere with glycogen synthesis.

The review also provided evidence that an active cool down generally does not improve and may even negatively affect performance if the time between successive training sessions or competition is > 4 hours.

An active cool down also has no substantial effects on next day(s) sports performance although some beneficial effects have been reported. They do not prevent injuries and preliminary evidence suggests that performing regular cool downs do not reduce the long term adaptive response.

However, most individuals perceive an active cool down as being more beneficial than a passive cool down. The effectiveness of an active cool down may differ depending on each individual's preferences and beliefs. Some athletes may benefit more from an active cool down while others may prefer to perform no cool down at all.

Some general guidelines for those who still wish to perform an active cool down. It should involve aerobic activities performed at low to moderate intensities to increase blood flow, but prevent development of substantial additional fatigue. 

It should involve low to moderate impact to prevent additional muscular damage or DOMs. It should be shorter than 30 minutes to prevent substantial interference with glycogen resynthesis. So make sure you eat/ drink quickly after exercise or competition. 

Some evidence also suggest that an active cool down should involve the same muscles used in the preceding activity. Now you know.

Reference

Van Hooren B, Peake JM (2018). DO We Need A Cool-Down After Exercise? A Narrative Review Of The Psychophysiological Effects And The Effects On Performance, Injuries And The Long-Term Adaptive Response. Sports Med. 48:1575-1595. DOI: 10.1007/s40279-018-0916-2

Cycling Helps Prevent Dementia?

Riding towards the sun

My laptop could not connect to the hotel WIFI network last weekend when I was away, so I'm only posting last week's post now.

Many of you reading this will know that on the Saturdays that I'm not traveling, I do a long bike ride with my usual cycling group. Since I was away, I also missed my Saturday bike ride.

I may have missed my Saturday ride, but I did get to read a very interesting article on cycling. Researchers found that sustained aerobic exercises (like cycling) may reduce the risk of dementia (Hou et al, 2025).

There were 479, 723 participants ( 260,730 females, 54.4 percent) with a mean age of 56.5 years in that study. These data were collected from the UK Biobank with the aim to investigate the long-term association between travel modes and dementia risk and to evaluate whether genetic predisposition can modify the association between travel modes and dementia risk.

To understand the link between brain health and common forms of travel, the participants were asked if they usually used motor vehicles, walking, cycling or public transport.

The researchers found that participants that cycled regularly (not including commuting to work) had a lower risk of developing dementia compared to those who walked, drove or used public transport. They were 19 percent less likely to develop all-cause dementia and 22 percent less likely to develop Alzheimer's disease.

The authors suggest that "this likely stems from cycling's higher aerobic intensity and cognitive engagement (e.g. navigation, coordination), which may enhance neuroplasticity more than walking alone". Other than regular exposure to fresh air from cycling, the physical demands of cycling plus the need to stay alert whilst on the roads or trails may help to maintain brain health.

This is supported by other studies (Erickson et al, 2011) where cycling or other aerobic exercises causes the hippocampus, the part of the brain responsible for memory formation, learning and spatial navigation to grow. Note that typically, the hippocampus reduces in size during late adulthood (from the mid to late 60's).

The authors concluded that the findings "suggest that promoting active travel strategies, particularly cycling, may be associated with lower dementia risk among middle-aged and older adults, which carries substantial public health benefits".

Now, that's a very good reason to keep cycling. Let's make our roads safer for cycling.

References

Erickson KI, Voss MW, Prakash RS et al (2011). Exercise Training Increases Size Of Hippocampus And improves Momory. ProNatl Acad Sci USA. 10897): 3017-3022. DOI: 10.1073/pnas.1015950108

Hou C, Zhang Y, Zhao F et al (2025). Active Travel Mode And Incident Dementia And Brain Structure. JAMA Netw Open. 8(6): e2514316. DOI: jamanetworkopen.2025.14316

Time Of The Day When You Are At Your Best

Picture from Healthyplace.com

I have been out of school for decades and have not sat for any tests or exams in quite a while. But I do see new patients almost every day I am working in our clinics. I do take plenty of "tests" too, since every single patient I see will evaluate my treatment and decide if I made them better.

You must be wondering why I am writing about tests this week, Well, the Singapore primary school leaving exams (PSLE) just ended this past week.  Parents whose children just sat for the exams must heave a collective sigh of relief now that it's all over. 

The typical start times for the PSLE oral exams are at 0800 while written exams generally commence at 0815 hours. That's definitely an early start for those taking exams.

Unlike the students sitting for exams, we usually see new patients in our clinic whenever we can fit them in for an appointment. This may not necessarily be the best according to a group of researchers who analyzed the results of over 100,000 oral exams. They found a clear Gaussian distribution (also know as the Normal distribution or bell curve) in pass rates that peaked at noon. 

Passing rate by hour 

Between 11 am and 1 pm is the best time (pictured above). Any earlier or later the chances of passing significantly decreased. In fact the earlier or later in the day these students took a test, the less likely they were to pass.

The reason being our cognitive (or conscious intellectual ability) performance improves over the course of the morning and then declines in the afternoon. We also may have declining energy levels later in the afternoon. If your exam is scheduled later in the day, you may also stress about it and this usually leads to poorer performance.

According to the author's, the examiner's cognitive performance and fatigue level also matters. Both the examiner and student will be at their peak level of performance during the mid day hours.

This all means that whenever possible if you have to take a test or exam, an important meeting or a job interview, you should schedule it between 11 am and 1 pm. It can be the difference between passing and failing. 

Perhaps we should only see new patients in our clinics between 11 am and 1 pm then. 

Reference

Vicario CM, Nitsche MA, Lucifora C et al (2025). Timing Matters! Academic Assessment Changes Throughout The Day. Frontiers Psychol. 16:1605041. DOI: 10.3389/fpsyg.1605041

Training In Hot Conditions Makes You Eat More?

Just after sunrise

After all the rainy days during the first 2 weeks of September, the temperatures were nice and cool. This past week it seems like "someone turned the tap off" and it's been way hotter. 

I weighed myself yesterday morning before and after my regular Saturday ride before work and found that I had lost 2 kg (mostly water) despite eating and drinking more during the ride. These 3 hour rides, when warmer, make me feel like I'm making my body work double time. I've noticed that when the temperature is higher, I need to eat more (during the ride) or else I cannot keep up with my friends.

On Saturday rides that are cooler, I sometimes don't even eat the banana that I bring with me and can still ride well without tiring.

Turns out that training in Singapore's heat and humidity does not just make one more comfortable in hot conditions, it actually changes how our muscles use energy (Xu et al, 2025).

The authors in the study quoted above show that a month of structured heat acclimation training can help change your metabolism to race stronger when it's hot and probably in cooler temperatures too.

The researchers split 18 trained middle and long distance runners into 2 groups. Both groups completed treadmill tests and metabolic assessments at temperatures of 30-32 °C (or 86-89 °F).

The first group trained in normal temperatures (20-25 °Celsius or 68-77 °F). The other group did 20 sessions of heat acclimation over 4 weeks. They ran in tem[eratures between 30-36 °C that pushed their core temperatures to 39-40 °C (or 102-104 °F).

No prizes for guessing that the heat acclimated group made more notable adaptations compared to the control group. Their core temperature during the subsequent treadmill test was lower by 0.4 °C, a clear sign of improved thermoregulation. They were also more efficient aerobically, as oxygen uptake improved by 4 and 3.7 percent at the *first and second ventilatory thresholds.

Plasma volume improved by 4 percent, haemoglobin by 2 percent and erythropoietin by 13 percent after heat acclimation, showing better oxygen support. All signs of heat adaptation.

At submaximal intensities (75 and 85 percent VO2 max, carbohydrate oxidation dropped by 15-19 percent in the heat acclimated group. The runners used less blood glucose and muscle glycogen, using more of the body fat instead. Exactly like I wrote above when I do not need to eat as much during cooler rides. In the picture above, carbohydrate (CHO) use and energy expenditure (EE) before and after control (black bars) and heat training (red).

Upon finishing the treadmill test, the heat acclimated runners cleared lactate more efficiently demonstrating improved recovery.

However, VO2 max did not change, suggesting that having a higher VO2 max (compared to someone else) may not mean you will race faster. The efficiency gains were more beneficial.

Take home message? Those of us who live in sunny and super humid Singapore can train almost all year round in such conditions. A 4 week block of 5 days a week may give you the metabolic edge of using less carbohydrates at higher intensities. This spares your glycogen stores and delays fatigue. The thermoregulatory and blood adaptations will help you stay cooler and deliver oxygen more effectively, especially if you are going to be racing in a friendlier climate. 

You will need to monitor the above parameters and allow for adequate recovery to get the benefits. This is when your blood, sweat (lots of it) and tears will pay off if you do it correctly.

Reference

Xu Y, Ye C, Ma S et al (2025). Four-Week Heat Acclimation Lowers Carbohydrate Oxidation Of Trained Runners During Submaximal Exercise In The Heat. Frontal Physiol. DOI: 10.3389/fphys.2025.1581594/full

*First ventilatory threshold (VT1) is when your breathing becomes noticeably deeper and lactate starts to accumulate in the blood. This indicates a shift from using mostly fat to carbohydrate during exercise.

VT2 or second ventilatory threshold occurs later, this is often when breathing is rapid, more labored leading to a sharp increase in carbon dioxide production. This is when a significant shift to anaerobic metabolism.

Still not too hot

How to Run Faster At The Boston Marathon

Picture from Runnersworld.com

I came across a recently published article detailing the training of 917 runners (495 women, 422 men) who qualified and ran in the 2022 Boston marathon (Lempke et al, 2025). The majority of them finishing in mid-3 hour marathon times. So definitely relevant insights for most serious recreational runners if you want faster marathon timings.

This interesting new study tracked running duration, volume, cross training and changes in training frequency between the last 12 months to 4 months before the race day. Yes, you read correctly, the runners were training 12 months in advance before racing. In addition, training intensity distribution like steady state runs, quality sessions and interval sessions were also analyzed.

Let me highlight the relevant findings. The study found that those who had longer running durations, higher quality ('hard') sessions, running distance and/or volume from 12 months to 4 months before the race was consistently linked to faster timings.

From 12 months to 4 months before the race, those who ran more than 10 hours weekly predicted significantly better performance than 5-7.5 hours, 2.5-5 hours and less than 2.5 hours per week of training (pictured above). For reference, the weekly mileage for the 495 women studied ran 64.4 ± 24 each week while the 422 men studied ran 67.6 ± 26.2 km on average.

Each extra run shaved 3-4 minutes off race time, while each extra quality session was worth 16-17 minutes better timing on average. Running an extra 1 km a week was worth about 3-4 minutes off marathon time.

In the final 4 months to race day, all of the above variables predicted better performance. Runners who included cross training in the final 4 months ran significantly better. Each extra session per week translated to being faster by 6 minutes of finishing time.

Reducing running frequency in the final 4 months improved performance. The runners who decreased their total weekly running sessions averaged 3 minutes faster than those who maintained or increased the frequency of their running sessions.

Just in case you got confused reading the above (I did at first) where the study said adding an extra run each week helps in the final 4 months, but also said a reduction in frequency was associated with better performance (pictured above). 

This means that between 2 runners, the runner running 5 times a week would be faster than another runner running 3 times a week. However, a runner who reduced their runs by 2 runs a week would run faster than another runner who only reduced their runs by 1.

Note that this study was survey based and depended on what the runners recorded in their training logs. Most runners tend to be meticulous about this, I know I was. There was also no mention of what the runners did for cross training. In addition to cycling or deep water running, I also did strength training.

Reference

DeJong Lempke AF, Ackerman KE, Stellingwerrff T et al (2025). Training Volume And Training Frequency Changes Associated With Boston Marathon Race Performance. Sports Med. DOI: 10.1007/s4027-025-02304-4

Rivals Or Brotherly Love

CL and I were rivals (actually more of a team mate as we were friends too) on the track when I was competing in my secondary school's track and field meet. We competed in the 800m, 1500m, 3000m and the 2000m steeplechase events. Though I won all 4 events, knowing CL was also training hard was a powerful motivator and it pushed us both to be better runners.

Yes, having a rivalry with a colleague, friend, or even your sibling can be stressful, but the right kind of competition will elevate each other's performance.

Carlos Alcaraz and Jannick Sinner are currently the top 2 tennis players in the world. They faced each other in 3 of the 4 Grand Slam finals this year including the recently concluded US Open where Alcaraz won. They currently have a super rivalry and their duels definitely push each one to higher heights. Just like Rafael Nadal and Roger Federer (pictured above) before them.

Research has shown that rivalries can have perks. One study showed that runners ran almost 5 seconds faster per kilometre in a race when a runner whom they considered a rival was also racing.

Another study showed that when different NCAA, NFL, NBA, and MLB team performances were analyzed, when a team's rival beat them in the post season one year, that same team does better the next year.

Of course there are occasions when rivalries can hurt us. One study showed that people can be unethical or even ruthless when competing against a rival because they really want to win.

A big difference between rivalries that boost us versus those that hurt us is whether they are viewed as long term relationships. Nadal and Federer are real friends after they step off the court after trying their hardest to beat each other on court. Federer wrote a moving tribute to Nadal just before his last tournament. Nadal did the same for Federer just before the latter retired too in 2022. 

It appears that Alcaraz and Sinner too have an underlying friendship besides their rivalry.

Picture from Cyclinguptodate.com

This is very much like what currently happens in cycling too. Current world cycling champion and 4 times Tour De France winner Tadej Pogacar is very friendly with his rivals, even driving to a race (Milan San Remo) together. 

Pogacar and Vingegaard

This was highlighted in a viral podcast by Lance Armstrong. Some cyclists may agree with Lance, but it's probably the character of Pogacar, Mathieu van der Poel and Jonas Vingegaard etc to be friendly and get along. That is definitely acceptable and touching even.

So, you do not have to be buddies with your rival, but surely you can be friends and have mutual respect for each other. Wish each other well and do your best to beat the other and this may help both of you soar to higher heights.

References

Kilduff GJ (2014). Driven To Win: Rivalry, Motivation And Performance, Soc Pysch Per Sci. 5(8): 944-952. DOI: 10.1177/1948550614539770

Kilduff, GJ,  Galinsky AD, Gallo E et al (2016). Whatever It Takes To Win: Rivalry Increases Unethical Behaviour. A Manag J. 59(5): 1508-1534. http://www.jstor.org/stable/26157371

Pike BR, Kilduff GJ & Galinsky AD (2018). The Long Shadow Of Rivalry: Rivalry Motivates Performance Today And Tomorrow. Psych Sci. 29(5): 804-813. DOI: 10.1177/0956797617744796

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