The Art and Science of Fitness | A midday snooze can optimise your productivity
Studies have found the hidden benefits of daytime napping. Here's what we know:
In today's society, there is a belief that sleeping, especially daytime naps, is a sign of laziness. However, many are unaware that before the widespread use of light bulbs, people typically slept in two to three bouts, totalling about 12 hours. With the advent of 9-5 jobs and artificial lighting, the norm shifted to a single bout of 7-9 hours at night. Unfortunately, this new pattern may not be natural for us, and we may not be aware of how it affects our productivity.
I spoke to Dr Manvir Bhatia, a senior neurologist and sleep medicine specialist at Neurology Sleep Centre, Delhi, and vice-president, Indian Society of Sleep Research about the role of midday napping. “There are definite benefits of midday naps that rejuvenate us and make us more productive. There are a couple of issues that we need to be careful about to make the most of those naps — time of the day to take the nap and duration of the nap.”
A study published earlier this year in the British Journal of Sports Medicine titled "Is daytime napping an effective strategy to improve sport-related cognitive and physical performance and reduce fatigue?" looked at exactly this. This study was led by Dr Arthur Eumann Mesas from Spain and consisted of team members from Chile, Brazil and Uruguay.
They looked at 3,421 research studies published on the topic and shortlisted 22 of them based on their stringent high-quality research criteria. These studies had been carried out in Tunisia, France, the UK, Japan, Thailand, and Australia. It is comforting to see this truly international cohort.
These 22 studies involved a total of 291 male participants, including 164 trained athletes and 127 physically active non-athletes who engaged in exercise and sports for over 7 hours a week. The participants' ages ranged from 18 to 35 years. However, it is important to note that the lack of female participants in the studies is a major limitation as sleep patterns and benefits may differ significantly between men and women due to hormonal differences. Additionally, it would have been beneficial to include participants from a wider age range, particularly those over 35, as this is when sleep may become more challenging for some individuals.
Now, in sleep medicine we’ve known, as Dr Bhatia also pointed out, the favourable effects of daytime napping on sports performance and on the level of fatigue perception in those with sufficient night sleep and those with partial sleep deprivation. But it goes back to Dr Bhatia’s two points: The time and duration of the daytime nap.
The study found the following: Post-lunch midday napping, approximately at 14:00 hours, lasting 30 to 60 minutes was found to have high supplemental beneficial effects on physical performance (eg. speed, strength, endurance, distance, power), promoting moderate improvement in cognitive performance (eg. reaction time, short-term memory, attention, alertness) and reduction in perceived fatigue or exhaustion after sports activity. The other finding was that to get the most benefit of the midday nap on sports performance was to have a minimum time gap of 60 minutes from getting from the nap and doing the physical activity, also called wash-out time.
The benefits mentioned above were observed primarily in individuals who already maintained a normal sleep pattern of 7-9 hours per night. However, those experiencing partial sleep deprivation also showed comparable improvements. While there is limited research on this topic, the current evidence is not conclusive. It is worth emphasizing that relying solely on midday naps to compensate for poor sleep at night is not sufficient.
Mesas et al highlight the effect of sleep deprivation. “Sleep deprivation promotes neurocognitive deficits, dysregulation of physiological functions regulated by the circadian rhythm (eg, temperature, blood pressure), and incomplete muscle recovery, which may accumulate over time in chronic partial sleep loss (restriction or deprivation).”
A good example of someone who benefited from midday naps was John F Kennedy. He suffered from chronic back pain in the last few years of his life. He was a hard-working president who was keen to make the world a better place. He would do his morning exercise and swim, followed by getting on with his official work. Post his lunch, he would ask not to be disturbed when he took a 1-2 hour nap. Once awake, JFK would take his second shower and resume work, fully rejuvenated, till about 8 pm.
Then there was Thomas Edison, who was known to sleep 3-4 hours a night, but what most aren’t aware of, is that he took long daytime naps. The world knows him for giving us the light bulb — but that was a stolen idea. What he definitely did, like most successful entrepreneurs, was monetise electricity by creating the electric metre and charging people for its usage. Those midday naps were helping him become productive, whether his ideas were original or not.
In the study, the beneficial findings of midday naps were more prominent in physically active adults, as compared to trained athletes. Mesas et al point out that it is necessary to consider that the margin for improvement in physical performance is smaller in trained athletes, as they have a higher basal performance level due to a more controlled routine of training and rest schedules, than in non-athletes. “It is also necessary to highlight that professional athletes report poorer sleep quality and hygiene than an age-matched cohort of non-athletes. Thus, the presence of chronic sleep-related problems may represent a barrier to the potential beneficial effects of napping on physical performance.”
To better appreciate the appropriate length of a nap, it is essential to first comprehend the physiological dynamics of sleep.
Sleep Cycle: An average sleep cycle is 90 minutes long. Ideally, there are 4-6 cycles of sleep every night. The first cycle is usually 70-100 minutes. The second cycle and beyond, are 90-120 minutes long.
Non-Random Eye Movement
• Stage 1: 1-7 minutes
• Stage 2: 10-25 minutes
• Stage 3: 20-40 minutes — during early sleep cycles, it’s longer and gets shorter as the sleep cycles progress
Random Eye Movement
Stage 4: 10-60 minutes — gets longer as the sleep cycles progress
Based on this science, Dr Bhatia suggests that when taking midday naps, don’t let it be longer than 15-20 minutes. You won't enter stage 3 sleep and will wake up refreshed and ready to get on with life. Mesas et al agree. “Short nap allows sleep to reach the superficial levels of sleep, which would be sufficient for partial relaxation.”
So why is a longer midday nap lasting 30 to 60 minutes better, if affordable? Mesas et al suggest, “a nap of longer duration that includes more time in deeper sleep stages may be required to mitigate the perception of fatigue and physical and mental exhaustion resulting from the sport activity.”
Dr Bhatia highlighted the issue of feeling irritable and groggy after a midday nap. To mitigate this effect, Mesas et al suggest a minimum gap of one hour between waking up from the nap and engaging in physical activity, exercise, or sports to achieve the maximum benefit of the nap. This approach addresses the undesirable consequences of sleep inertia and enhances physical performance to an optimal level.
The other point Dr Bhatia raised was about the timing of the midday nap. “If the nap is closer to the latter part of the day, it disturbs the sleep at night.” This again was addressed well by the findings of Mesas’ study. The best time to take a midday nap was found to be soon after lunch, around 2 pm.
If you're wondering how you could take a midday nap in the chaos of our busy lives, you need to learn a thing or two from the legendary Napoleon Bonaparte. He was full of energy and extremely focused during his military campaigns, but also was gifted with the ability to take short midday naps on the battlefield itself, not disturbed even by the booming of the cannons.
Take home message: If you can afford to, especially if you are working from home, take midday naps lasting 30 to 60 minutes at around 2 pm soon after lunch. Expect to be performing at your peak level mentally and physically after about an hour from waking up. However, for the majority of us, a 15-minute midday nap around 2 pm is sufficient. Regardless, it is imperative to ensure that night-time sleep is not compromised. Regardless, it is imperative to ensure that night-time sleep is not compromised.
Keep miling and smiling. And when you get a chance, take a short nap, like the hare.
Dr Rajat Chauhan (drrajatchauhan.com) is the author of The Pain Handbook: A non-surgical way to managing back, neck and knee pain; MoveMint Medicine: Your Journey to Peak Health and La Ultra: cOuch to 5, 11 & 22 kms in 100 days
He writes a weekly column, exclusively for HT Premium readers, that breaks down the science of movement and exercise.
The views expressed are personal