Working out when to train, rest and sleep is critical for elite athletes’ performance – and now you can tap into the science to get the most out of your workouts, whether you’re a night owl or early bird.
What are circadian rhythms and why do they matter?
‘Chronobiology is the study of natural rhythms in biological processes,’ says Professor Greg Murray, Director of the Centre for Mental Health at Swinburne University. ‘Annual, seasonal, monthly, daily and more frequent patterns are recognised. In humans and many other species, rhythms of about 24 hours (‘circadian rhythms’) play an important coordinating role,’ he says.
You’ll have heard of circadian rhythms before – your internal body clock that cycles between wakefulness and sleepiness at regular intervals. Sync your body clock right, and you’ll tap into a natural cycle of energy and recovery. Try and fight that clock, and you’ll be snoozing at your desk come 3pm or wired yet tired at midnight.
And it’s not just about harnessing the energy to meet a deadline or smash a training session. Circadian rhythms can also even influence your mood.
‘We tend to feel more positive and engaged in the early afternoon,’ says Murray, while ‘abnormalities in circadian function are associated with mood disorders such as depression and bipolar disorder.’
In fact, a study in the journal Frontiers in Neurology noted that circadian rhythms contribute not just to physical performance, but hormones, glucose tolerance, blood pressure, core body temperature and cognitive processes, including reaction times, alertness and memory speed.
Pick your activity time
So how can you align your schedule with your body clock to boost your performance, whether at work or in the weights room?
‘Evolution has worked out that sunrise and sunset are so important that they should be predicted, rather than reacted to,’ says Murray. ‘The body clock (‘circadian system’) is adapted to ensure we are primed to act at the right time in the 24 hour light/dark cycle.
‘We are strongly primed, for example, to be asleep at 3am and out in the world at 3pm. We are primed to seek rewards in the early afternoon and to feel like we want rewards (positive moods).’
This concept of mood, motivation, behaviour and reward is central to Murray’s study of chronobiology. ‘When we look at motivation and human choices through the lens of time of day, the same behaviour might be useful at one time of day and counterproductive at another time.’
Feeling mentally switched on and in full creative flow is useful at 10am when you’re powering through a business strategy – not so much at 10pm when you need to be powering down for a restful night.
How to alter your body clock for peak performance
One of the most important factors in syncing your circadian rhythms for performance is sleep. Studies link sleep deprivation with reduced performance, increased rate of injury, reduced muscle glycogen stores and poor post-exercise recovery.
Your rate of perceived exertion (RPE) will also be higher – you’ll feel like you’re working harder just to keep up with that training session you’d usually crush given adequate sleep.
‘Sleep provides the opportunity for our body to ‘reset’,’ says Coffey. ‘It’s the time when our cells and systems are restored and regenerate. During sleep there are very low metabolic demands, and the body can focus on restoring the immune system and hormone balance, regenerate energy stores and repair damage, and importantly, the nervous system can shut down and take a break.
‘Good quality sleep translates to optimal functional capacity for high-quality training and maximises the adaptation response to exercise.’
In a nutshell? Prioritise sleep to increase the benefits of your body clock and your training.
What time should you train?
Sunrise run or post-work workout? When is best to maximise your performance, results and sleep?
Aligning your training with your personal circadian rhythm can boost your performance. University of Birmingham researchers found that athletic performance can vary by up to 26 per cent across the day, depending on the athlete’s circadian rhythm.
‘For the average person, optimal time of athletic performance generally seems to be in the evening around the time of peak core body temperature,’ says Murray.
‘There is some research to suggest that you may be more metabolically efficient for endurance training in the afternoon and also potential to be stronger in the afternoons,’ agrees Dr Vernon Coffey, Associate Professor of Exercise & Sports Science, Bond University.
Great news if winter has you diving under the doona when that dawn alarm sounds.
That said, afternoon workouts might also have you feeling restless when it comes to laying your head on a pillow.
‘Vigorous training raises whole-body metabolic rate and stimulates many psycho-physiological processes that tend to put us in an elevated state of arousal or activation,’ says Coffey.
‘You could say that it switches us ‘on’, especially if you take part in sport or competition. The closer this occurs to the start of your normal sleep pattern, the more difficult it is to return to your baseline level. [This] makes it hard to get to sleep or promotes a disrupted sleep.’
But before you ditch the after-work yoga or post-dinner walk for fear of zapping your zzzs, remember intensity also matters.
‘The higher the intensity of exercise, the greater the activation of physical and cognitive responses,’ says Coffey. ‘High-intensity interval training or a heavy resistance training session will be a stronger activator than yoga or Pilates, or going for a walk.
‘There are always differences in individual responses and variation between individuals, but while hard training later in the evening will make you feel physically tired, most people will find they can’t shut their brain down.’
In fact, training intensity can influence sleep quality regardless of whether you HIIT it in the morning or push for a personal best at night. A study in Physiology & Behavior showed that moderate intensity training led to calmer sleep than high intensity training, regardless of the time of day the athletes trained.
What’s important are the recovery demands of the exercise you’re undertaking – evening training at lower intensity and high intensity morning training make more modest demands on your body to recover at night, as opposed to a max effort weight lifting session or sprint intervals before bed.
How to cheat on your body clock
But what if you can only train after work, or you need strength to power through an early morning session?
‘There is emerging evidence suggesting you may be able to change the settings of the molecular clock in our muscles if you are consistently training at a similar time of day,’ says Coffey.
Researchers showed that increasing your warm-up time by 20 minutes for morning sessions to mimic the peak core body temperature we normally have in the late afternoon increases performance. And if you’re naturally a night owl who loves a late workout, be aware that your sleep quality may be affected and make allowances the next day, with an easier session or recovery day.
Personalising your training to your body
While the research might indicate we’re stronger in the afternoon, or get better sleep quality if we train in the morning, the overwhelming predictor of peak performance is syncing your training time with your ‘circadian phenotype’ – a term used by sleep scientists to describe your preferred wake/sleep cycle. Early birds perform better in morning tests, while night owls peak during evening training.
‘Being aware of your own rhythms of mood [and] energy can be good for quality of life,’ says Murray.
‘Evening types benefit from understanding why they simply can’t get to bed early enough to wake up rested for work or school.’ Rather than lying in bed worrying about falling asleep or committing to an early run when you’re a night owl, accept your own circadian rhythm and try to work with it.
‘Knowing that we have waxing and waning motivation across the day can help us accept poorer performance and be kinder to ourselves,’ says Murray.
Top tips to sync your body clock for performance
1. Work out whether you’re a lark or an owl. ‘You probably already know, but try taking it into account as you make choices,’ says Murray.
2. ‘Pay attention to your own daily rhythms, which will vary for different activities,’ suggests Murray. If you’re at your most creative in the morning, ditch the email and meetings until after lunch. If you feel most powerful and motivated after work, schedule training accordingly.
3. Wake up at the same time each day: This is important seven days a week, not five, notes Murray. Consistency is key with circadian rhythms.
4. Track your sleep. ‘A good place to start is to try and understand how well you sleep by keeping a sleep diary. You can combine this with your training diary and use the information to identify what is the best timing for you to undertake your training when your energy levels are high, and disruption to sleep is minimised,’ says Coffey.
5. Don’t forget your accessories: If you love to train earlier in the day (or your competition, start-time or race wave is scheduled early), spend extra time on your warm-up to mimic the increased core body temperature you’d naturally have later in the day.
6. Reward yourself for your achievements. If intrinsic rewards motivate you, the very act of training will be reward enough. If you need a stronger push, set yourself an extrinsic reward – be it a new gym kit, a massage, or whatever motivates you to get up and move consistently.
The top takeaway?
Adapt your training schedule to your individual rhythms: If you love to train early, get up and at ‘em. If after work is your time, train evenings. Just make accommodations to your training intensity and sleep cycles to ensure you get enough rest, regardless of when you train.