14 Day Lag Period Between Sleep Deficit And New Injury

Picture by Jeffrey Bown from his book Goodnight Darth Vader

Well, it's that time of the year again, where school has ended (for Singapore schools) and work in the office starts to wind down. Many of our patients are already traveling before the Christmas holiday.

Many of us, in this last month of the year, will experience less sleep due to travel, parties, family, children and shift work.

Though we would love to catch up with sleep when sleep is disturbed, even with training/ exercising taking a lower priority, it becomes more difficult with all the committments.

I often tell my patients (who are still training seriously) that there is up to 51 percent increased risk of injury especially for endurance athletes who get less than 7 hours of sleep per day in the last 2 weeks (Johnson et al, 2020).

The study recruited runners, triathletes, swimmers, cyclists and rowers. Subjective health complaints (SHCs) like psychological/ lifestyle factors, cardiorespiratory and gastrointestinal problems to investigated to see if they were associated with sleep quality, training load and new injury episodes.

Applying a 7 day and 14 day lag period, a shared frailty model was used to investigate new injury risk associations with total SHCs and sleep quality.

The investigators found that 7 day lag psychological/ lifestyle SHCs were significantly associated with new injury risk. This was in contrast to cardiorespiratory and gastrointesinal SHCs were not significantly associated with new injury risk. 

New injury risk had a significant increased association with a 14 day lag if there was less than 7 hours of sleep per day. There was no significant association with total SHCs, sleep quantity and training load factors.

The authors concluded that athletes need to be aware of the lag period between low sleep quality and its subsequent impact on new injury risk. In order to minimise the risk of new injuries, psychological/ lifestyle SHCs and sleep quantity should be considered.

Be mindful. Bear in mind that this end year period may be a time when we are most susceptible to new injury if we are deprived of sleep.

Reference

Johnston R, Cahalan R, Bonnett L et al (2020). General Health Complaints And Sleep Associated With New Injury Within An Endurance Sporting Population. J Sci Med Sport. 23(3): 252-257. DOI: 10.1016/j.jsams.2019.10.013

If Only You Know The Power Of Sleep ....

The power of sleep

While I was still working at the Singapore Sports Council or SSC (now known as the Singapore Institute of Sport or SSI) I used to travel a lot with the Singapore badminton players while they were competing or training overseas.

And no matter where the badminton players were training or competing, their normal routine would be training in the morning, break for lunch and there would always be a nap after lunch before training again. Even our national table tennis players took daily naps when they were not out buying eggs (okay I'm just kidding). No disrespect meant!

Why am I writing about sleep here? You and I know that a lack of sleep can lead to negative consequences. It can affect your mood, cognitive function and physical performance. Few studies though have looked at the opposite - the effects that sleep extension can have on performance.

The American National Sleep Foundation recommends 7-9 hours of sleep a night for adults for general health and well being. But a study on Stanford basketball players by researchers Cheri Mah and colleagues showed that with 5-7 weeks of sleep extension, i.e. going to bed earlier and waking later, subjects had improved basketball performance, reaction time and running speed.

The researchers concluded that "extended sleep beyond one's habitual nightly sleep likely contributes to improved athletic performance."

As it is, most of us will find it difficult (myself included) to find more time to sleep. Our smart phones, the iPad, Netflix etc are big distractions. Yes, I have to stay up writing this so you can read it. Well, I'm not racing anymore.

Many of you will focus on improving your performance by training harder and smarter, but those improvements become smaller and more difficult to obtain after a while. Your fellow competitors will likely swim/ bike/ run similar intervals in addition to hitting the weights room etc. It all comes to to all the fine details. Some of these small gains (like sleep extension) are found outside of aerobic and interval training.

It's probably easier to change your bedtime to get more sleep by gradually going to sleep earlier. Try to go 15 to 30 minutes earlier each night to find a good time for yourself.

Sleeping in never happens for my wife and I, our boys are up by 6 am or earlier most mornings. If you can sleep in good for you.

I remember attending a meeting prior to the 2004 Athens Olympics where the then Director of High Performance, SSC was questioning the then CEO of Singapore Badminton Association (SBA) why the Singapore badminton players needed naps when they could be working part time or studying in between training as what many of the elite athletes at the Australian Institute of Sports do.

Then CEO of SBA's reply was if it (naps) has the potential to impact performance in a positive manner, then we try to take care of it.

In the picture below you see me more excited than Ronald Susilo after he defeated Lin Dan in the 1st round at the 2004 Athens Olympics.

That's how we should help our athletes.

Reference

Mah CD, Mah KE et al (2011). The Effects Of Sleep Extension On The Athletic Performance Of Collegiate Basketball Players. Sleep. 34(7): 943-950. DOI: 10.5665/sleep.1132

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