Exercising Before Sleep: Does Exercise Affect Sleep?

One question we often hear is, "I'm busy all day – is it okay to exercise in the evening? Will it ruin my sleep?" The old advice used to be a pretty strict "no." Exercise by nature raises one’s core body temperature and one of the key sleep hygiene tips to get quality sleep is to lower one’s core body temperature a few degrees. Sleeping in a cool, dark room is scientifically proven to improve one’s sleep quality in healthy adults. However, like many things in medicine and physiology, our understanding has become more nuanced over time.

Let's talk about how exercise really affects your sleep, and whether your evening workout fits into a healthy sleep routine.

The Foundation: Exercise is Fundamentally Good for Sleep

First and foremost, regular physical activity is one of the most powerful tools we have for improving sleep efficiency and sleep quality overall. Patients who incorporate physical exercise into their lives consistently report better sleep. From a medical standpoint, we see that moderate-intensity exercise helps to:

• Improve Sleep Efficiency: Meaning you spend more time actually sleeping while you're in bed.
• Enhance Sleep Architecture: It can increase the amount of time you spend in deep sleep, which is crucial for physical restoration and feeling refreshed.
• Reduce Sleep Latency: Helping you fall asleep faster.
• Act as a Stress Reliever: By reducing tension and anxiety, two significant contributors to insomnia.
• Help Regulate Your Body Clock: Over time, consistent exercise helps reinforce healthy sleep-wake patterns.

So, the baseline message is clear: getting exercise is highly beneficial for your sleep health. The question then becomes about timing and the type of exercise.

Addressing the Old Concern: "Getting Wired" Before Bed

The traditional advice to avoid exercising close to bedtime stemmed from logical physiological responses to physical exercise. If one performs a vigorous exercise minutes before bedtime, what happens is:

• Increased Heart Rate and Circulation: Physical exertion elevates your heart rate and gets blood flowing, which is stimulating.
• Elevated Core Body Temperature: During exercise, your body temperature rises. As sleep onset requires a slight drop in core temperature, it seemed counterproductive to raise it right beforehand.
• Release of Neurotransmitters: Exercise releases endorphins and adrenaline, which can promote alertness and energy.

These physiological effects would make it difficult to transition into a restful state necessary for sleep, especially if such physical exercise was performed a few minutes to a couple of hours before bedtime.

The Updated Clinical View: It's More Flexible Than We Thought

However, what we understand now based on more recent studies of sports medicine and clinical observation is that the negative impact of evening exercise on sleep time and efficiency isn't a universal rule, and it depends heavily on several factors - the time of day of your exercise and the type of exercise. 

• Intensity Matters: High-intensity exercise (like vigorous cardio or heavy lifting) completed very close to bedtime (say, within an hour) can still be disruptive for some individuals due to the pronounced physiological arousal. Your body might not have sufficient time to "downregulate", which is shifting the nervous system from a “fight or flight” state to a “rest and digest” state. Such vigorous workouts prevents some from being able to fall asleep, much less get restful sleep.
• Moderate to Low Intensity is Often Acceptable: For most people, moderate-intensity exercise like a brisk walk, cycling at a comfortable pace, yoga, aerobic exercise, or stretching, even if completed within an hour or two of bedtime, do not negatively impact sleep. In fact, the tension released from these activities can sometimes promote sleepiness. This shows that the type of exercise matters.
• The Temperature Cycle: While exercise raises temperature, the crucial point for sleep is the subsequent decrease in core temperature that happens during the recovery phase after you finish exercising. If you allow enough time for this cool-down period before getting into bed, that falling temperature can actually facilitate slow-wave sleep. If you’re getting a vigorous workout minutes before bedtime, you would not have enough time to cool-down before bed. However, if you were to do your workout, even a vigorous one, several hours before bed, you might have sufficient time to allow for that subsequent decrease in core temperature that can help you get better sleep quality.

The Most Important Factor: Your Individual Response

This is where being attuned to your own body comes in. What works for one person might not work for another. Some individuals are highly sensitive to the stimulating effects of evening exercise, even if completed a couple of hours before bed, while others can run a few miles minutes before bedtime and still sleep like a log.

Pay attention to your own experience. If you notice that finishing a particular type of workout at a certain time consistently makes it harder for you to fall or stay asleep, then adjust that specific timing or type of exercise.

Recommendation: Prioritize Getting Exercise, Then Optimize Timing

Given the overwhelming benefits of regular exercise for overall health and sleep quality, our primary recommendation is to ensure you are physically active consistently. If the evening is the only realistic time for you to exercise due to work or life commitments, then by all means, exercise in the evening! However, try to get your workout in as soon as possible after work to give yourself a few hours before sleep time. Physical exercise has enormous benefits to other parts of your health, including your cardiovascular health and respiratory health, and it would be a pity to avoid physical exercise because you are fearful that it would impact your sleep quality.

Practical Strategies if You Exercise Later

If your schedule means you're exercising in the evening, consider these strategies to support your sleep:

• Allow Adequate Cool-Down: Try to finish more vigorous exercise at least 1.5 to 2 hours before your target bedtime. This gives your body temperature and heart rate time to return to baseline and facilitates the sleep-promoting temperature drop.
• Consider Exercise Type: If intense evening workouts seem to disrupt you, try switching to moderate-intensity cardio or relaxation-focused activities like yoga in the later hours.
• Maintain Your Bedtime Routine: Go through your usual calming activities after your workout and cool-down period.
• Hydrate Appropriately: Support your body's recovery through drinking sufficient water right after your workout but stop at least 1.5 hours before bedtime. This would prevent your sleep quality from being disrupted by frequent urinations during the night.

Working Out Before Your Night Shift

If your work is primarily during the night, working out before your night shift can be very beneficial. You should consider these aspects:

• Boosts Energy and Alertness: Generally a workout before your shift can help to increase your energy, improve your mood, and enhance your focus, helping you to stay alert throughout the night
• Do Not Overdo It: The type of workout does matter as well. Avoid very vigorous or long workouts that might drain your energy and leave you feeling sore during your work shift. A moderate-intensity workout or some aerobic exercise is ideal. 
• Hydration and Nutrition: Make sure you fuel up with a balanced meal or snack after your workout to sustain your energy for the night ahead. Don’t overload on sugary foods after as that will just cause your energy levels to quickly peak and then crash, making you feel sleepy.
• Sleep Deprivation: If you are already sleep deprived, some light physical exercise like stretching or yoga might be better than a strenuous workout to avoid additional fatigue. 

Exercising Before Bed Helps You Lose Weight

Exercising before bed can help with weight loss, but it depends on the type of exercise, intensity, and your overall habits. Here’s what to know about this commonly asked question:

• Calories burned are the same: Whether you work out in the morning, afternoon, or night, burning calories through exercise contributes to weight loss as long as you’re in a calorie deficit. Your time of working out doesn't change the calories burnt. However, morning workouts, if not too exhausting, tend to boost your mood and give you more energy for the rest of your day - as a result, you could end up burning more calories than nighttime workouts.
• Sleep quality matters: Intense exercise right before bed might make it harder to fall asleep for some people, as mentioned above, which could affect weight regulation over time. Your heart rate might still be high or you might have tighter muscle tension post nighttime workout, both of which make it harder for you to fall asleep. Additionally, vigorous exercise can lead to increased blood flow to your muscles, which can increase fluid shifts towards the head and neck, potentially narrowing your airway and making it more likely to collapse during sleep, thereby worsening obstructive sleep apnea. Post-exercise fatigue can further contribute to a weakened upper airway, increasing the risk of collapse and also worsening obstructive sleep apnea. Poor sleep could cause weight gain as sleep is critical for your body to repair cells and muscles, produce cytokines that help fight infection, and inflammation, and more. If you don’t get enough restful sleep because of vigorous exercise right before bedtime, this could cause you to build up more inflammation in your body and cause weight gain.

Exercising before bed can absolutely be part of a weight loss plan, as long as it doesn’t interfere with your sleep or recovery.

Exercise Is Beneficial For Sleep

The notion that exercising before bed is strictly bad for sleep is largely outdated. Regular exercise is incredibly beneficial for sleep health. While high-intensity exercise immediately before trying to sleep might be disruptive for some individuals, moderate or low-intensity evening activity is often perfectly fine and can even be helpful. The key is listening to your own body, prioritizing consistent exercise whenever you can fit it in, and making adjustments based on your personal response.

If you have chronic sleep difficulties or underlying health conditions, always discuss your exercise habits and sleep concerns with your doctor. We can help you develop a plan that supports both your physical activity goals and your sleep needs.