What is a good night’s sleep? Like a good meal: it depends…

What do you consider to be a good night’s sleep?

Daria shevtsova

Daria Shevtsova

What if a good night’s sleep for you were to fall asleep easily and remain in Morpheus’ arms until the gentle sound of your alarm-clock goes off? Or rather dream vividly and when you wake up get the answer to the question that has been gnawing at you for such a long time, in the easiest possible way? Or even wake up in the early morning, realise with pleasure that you still have the freedom of lying in bed, and put yourself in snooze mode for another few hours? To this easy-looking question, there are a multitude of possible answers. Answers that might be as diverse and different to the following one: for you, what is a good meal? I suggest we apply the analogy of a good night’s sleep to a good meal. Let’s consider for a moment the experience of a nice dinner. Surely, elements such as the quantity and quality of food contribute to feeling satisfied. If some of you enjoy an all-you-can-eat buffet, others focus more on the quality of the products. The sleep quantity (number of hours of sleep per night) as well as its quality also contribute to feeling satisfied by a good night’s sleep. But that is not everything. To enjoy a nice dinner, the presentation of the dish, the price or even the atmosphere are other elements to take into consideration. If some of you are looking for a restaurant dinner, others would prefer a home-cooked meal… In the same way, our sleeping environment contributes to good sleep quality. Finally, feeling satisfied by a night’s sleep cannot be reduced to the quantity and quality of your sleep. A good night’s sleep is the sum of multiple components: 1) its subjective quality; 2) sleep onset latency or the time required to fall asleep; 3) how long it lasts; 4) the efficiency of your sleep; 5) possible disruptions during the night; 6) possible medication intake; 7) difficulties encountered during wake time. Thanks to this questionnaire, you will be able to seriously assess your sleep and understand where you’re at. And then follow up on your progress, month after month. Defining a good night’s sleep is pretty complex, and the retained definition varies from person to person. These seven components are measured by a questionnaire called the “Pittsburgh Sleep Quality Index” or PSQI which evaluates your sleeping patterns throughout the last month. In the meantime, for those of you who wish to control their sleep, a multitude of solutions and strategies exist which can help improve the quality of your sleep. And to stretch the analogy, the need or the act of napping does not say much about your overall satisfaction in relation to your nocturnal sleep, just as snacking after a meal does not necessarily mean that you did not enjoy it!                        

Mathieu Nedelec, sport scientist in charge of research projects on sleep and recovery. I teach best practices to improve sleep and performance. I will read your answers carefully and let you know when my next posts will be published.

Evening exercise and sleep

Evening work-out or a good night’s sleep: do we really have to choose? 



Monday night, 10:30pm in Paris. As one of January’s cold snaps hits me, I walk home as briskly as possible. When turning a corner, I am attracted by a particularly bright window. As I get closer, a loud and catchy song becomes clearer to me. A gym! Behind the window, a dozen athletes are trying to keep up with the coach’s pace. A barely visible drop of sweat is running down his forehead, and he has the decency at the end of the class not to tell his students that it is his seventh class of the day… This ordinary urban event is the opportunity to answer one of the most frequently asked questions during my interventions: “does evening exercise disrupt my sleep?”.

Medical doctors and public opinion generally tend to discourage intense evening exercise, during the period leading to bedtime. Such an exercise would impair the quality of sleep during the following night. Today, there is very little proof in scientific literature to support the evening sofa option rather than outdoor running or on a treadmill in the gym. In 1976, Browman and Tepas certainly showed an increase in sleep onset latency - or the time required to fall asleep - following late-night exercise. The significant increase in sleep onset latency was of 6 minutes after a 45-min cycling session performed only five minutes prior to bedtime! As fast as you may be to shower, go home and enjoy a little snack, we can bet that the recovery period between the end of your session and bedtime is longer… Several studies have shown the lack of effect or even positive changes on sleep from an evening exercise. For example, Buman et al. (2014) have shown, in a large cohort of 1 000 adults, that fans of evening exercise - performed less than 4 hours before bedtime - display a similar sleep or a better sleep on exercising days compared to resting days. What’s more, a meta-analysis gathering the results of almost 3 000 adults concluded that exercising less than 3 hours prior to bedtime is beneficial for sleep, i.e. less wake after sleep onset and less light sleep     throughout the night (Kredlow et al., 2015). And what about exercise intensity? Performing an exercise subjectively perceived as difficult one and a half hours before bedtime is associated with better sleep quality and a reduction in sleep onset latency (Brand et al., 2014).

Our core body temperature follows a circadian rhythm, very close to 24 hours. It is at its lowest around 3:00 or 4:00am and increases progressively before peaking between 6:00 and 8:00pm. Between these hours, is the ideal window to outdo your personal record! Sleep initiation is then linked to a decrease of your core temperature (approximately 0.5 to 1°C) and deep sleep is made more possible during the first part of the night if our core body temperature is reduced. The general advice of not exercising in the evening is mainly based on the assumption that evening exercise, especially if intensely performed, will increase core body temperature and threaten sleep quality. Reality is much more complex. To see clearer, we studied the influence of a high-intensity trail undergone in the lab at 9:00pm on well-trained runners’ sleep assessed by polysomnography (maximal aerobic speed superior to 18 km/h and VO2max of 70mL/min/kg). Results showed a slight change in sleep architecture during the night after exercising compared to the control condition. Core body temperature and heart rate were significantly increased throughout the first part of the night compared to the control condition. Another article which was published at the same time (Thomas et al., 2019) showed that an intermittent running exercise (6 sets of 5 minutes at 90% VO2peak; and 5 minutes recovery) at 6:00pm increased total sleep quantity during the subsequent night, even though an increase in heart rate was also observed.

It seems that evening exercising and a good night’s sleep are compatible! Regular physical activity paves the way to good sleep and long-term health. In order to maximise your chances, here is my list of strategies to favour your sleep after exercising in the evening:

1. Limit light exposition, especially to screens, and possibly wear tinted glasses.

2. Choose a milky beverage over water to ensure rehydration

3. Eat a high glycemic-index snack

4. Drink tart cheery juice and food rich in tryptophan (e.g. turkey, pumpkin seeds)

5. Set up an adequate sleeping environment: cool (18 to 19°C), peaceful and dark

6. Try out breathing exercises, which we will discuss next time

Mathieu Nedelec, sport scientist in charge of research projects on sleep and recovery. I teach best practices to improve sleep and performance. I will read your answers carefully and let you know when my next posts will be published.

Sleep in Western countries

And what about you, do you get enough sleep?

Acharaporn kamornboonyarushs

Here we are in 2020 and it’s already a new decade. New Year’s night was a very short, festive and maybe even sleepless one for some of you. And what if taking care of your sleep was your new year’s resolution? Surveys led by public health authorities in Western countries are clear. A large proportion of us doesn’t get enough sleep. French people, for example, sleep on average 6 hours and 42 minutes per 24-hour cycle. The average sleep duration has reached the critical level of less than 7 hours! This is a public health issue. An organization of sleep experts recently penned an article with the provocative title: “Our lack of sleep is killing us”. Approximately 30% of the population sleeps less than 7 hours a night. During one of your next nightly awakenings, just be curious and look out of your window onto the sleeping city. You will then be able to count the lit-up windows, rather than sheep, and will realize that you are far from being the only one… However, sleep plays a crucial part in physical (thanks to deep sleep) and psychological recovery (the role of rapid eye movement REM sleep). The recommended sleep duration for an adult between the ages of 18 and 65 is anywhere between 7 to 9 hours. Rest assured: solutions exist! First of all, sleep must be reinserted into a general context of sleep-wake rhythms. The quality of your night will depend on the quality of your day. Regular physical activity and good emotional management are already strong allies. Moreover, similarly to a switch, strategies exist in order to easily switch from wake to sleep mode throughout the evening. And then swiftly from sleep to wake mode in the early hours of the morning. Light therapies, nutrition, bedding, cooling down, sleep extension, etc. are examples of some of these strategies. Several scientific studies have revealed the superiority of cognitive behavioural therapies over sleeping pills, without the potential side effects linked to the intake of medication. There is an urge to take action and care for your sleep! We will accompany you in this ever-so-crucial process.

Mathieu Nedelec, sport scientist in charge of research projects on sleep and recovery. I teach best practices to improve sleep and performance. I will read your answers carefully and let you know when my next posts will be published.