Morning, noon or night. Is there a sweet spot for exercise to promote a restful slumber?
Just like evolutionists have been pondering the age-old question ‘what came first, the chicken or the egg?’ fitness professionals have been debating ‘when is the best time to exercise?’ for years. In one corner you have those who think morning is the pinnacle for training as it sets you up for the day, helps you make better life choices and gets those endorphins pumping early on. Training at night, even gentle forms, are a no-no as anything remotely stimulating only intensifies cortisol levels and causes problems for sleep.
In the other corner, you have the school of thought that doing high-intensity forms of exercise are perfect for evenings as they leave you fatigued and ready for slumber, while practices such as yoga and Pilates are restorative and create a peaceful setup for good sleep hygiene.
So, who’s right? Let’s look at the science.
According to a study by the Department of Health and Exercise Science at Appalachian State University, participants who worked out in the morning had longer and deeper sleep cycles than those who exercised later in the day. Another benefit of a morning workout is that you’ll make better food choices throughout the day so it might be easier to say no to sugar-loaded treats and insulin spikes resulting in poor sleep later on. A study published in Medicine and Science in Sports and Exercise looked at how women responded to food after working out first thing in the morning. After a brisk 45 minute walk, it found the women were less distracted by the food in the photos they were shown, compared to when they failed to exercise at all. And not only that, but another study in the British Journal of Sports Medicine found that morning exercise improves attention, visual learning, and decision-making making it easier to pass on the booze and late night Netflix binge – both of which can disrupt your sleep cycle.
Generally, you’re not at your best in the morning and your body can feel stiff and sluggish. However, your body temperature increases during the day and peaks in the afternoon. This is usually when you feel more energetic and when your muscles are working at their most effective. A study published in the Journal Of Sports Sciences found that between 4-8 pm, participants' grip-strength, vertical jump, and reaction times were at their best.
Now this is where it’s gets interesting, a study by the Central Queensland University in Australia, found that people who performed moderate or intensive exercise three hours before bed fell asleep faster than those who didn’t. However, it’s all about timing as exercise releases endorphins and this chemical activity can keep some awake at night. Therefore, it’s recommended that exercise stops at least 90 minutes before bedtime to allow endorphin levels and core body temperature (a rise in core body temperature signals to our body clock that it’s time to wake up) to return to normal. There have been several more studies showing that evening workouts do not disrupt sleep with one stating that when endurance runners did high-intensity, early evening exercise it actually improved their sleep. And if you’re into strength training, there’s positives for you too. A study in the Journal for Strength and Conditioning Research found that those who lifted weights in the evening got better quality sleep and slept for longer than those who did the same workout in the morning.
Just remember however, when it comes to exercise, a workout at any time of day is better than no workout at all - so get training.