Ask the Expert: What Is the Best Time of Day to Exercise?
The best time of day to exercise is when you have the most energy and motivation. But, as long as you’re smart about how you exercise, feel free to perform cardio, HIIT, and weightlifting exercises at any time of day and produce results. Note that when you consistently work out, the more likely you are to see results.
When Is the Best Time of Day to Exercise?
Potential benefits of morning workouts: Greater weight loss through improved fat burning.
Potential benefits of afternoon/evening workouts: Improved aerobic performance and faster strength gains.
Having the motivation to work out is crucial. Missing your optimal window for training is no reason to skip today’s workout. Unless you’re injured, sick, or over-trained, exercising is better than not exercising, so always schedule your workout when you have the best chance of getting it done.
If you’re a night owl, work out at night. Morning person? Hit the gym first thing. The most significant physiological changes happen to your body when you push yourself further than you’ve pushed yourself before.
Read on for the three best times to work out, depending on your goal.
1. When your glycogen stores are full
Best for: Boosting aerobic performance, especially endurance
Best time: Late morning, afternoon, and early evening
Your body can push itself longer and harder aerobically if you begin your workout with a full tank of muscle and liver glycogen, which is then stored for your body’s primary fuel, glucose.
At night, your body builds up its glycogen stores. Theoretically, it’s possible to wake up and train in the morning before you’ve eaten and still have enough energy to get through a workout. Most of us, especially when we’re training hard and not eating a ton, will burn through glycogen recovering from the previous day’s activities. That’s because:
- Glycogen is replenished by carbohydrates and is extinguished very quickly through exercise, brain activity, and most other tasks.
- Glycogen fluctuates throughout the day and is always highest in the hours after you digest a meal containing carbohydrates.
- Depending on your eating schedule — your body is probably primed for peak exercise in the late morning, afternoon, or early evening.
Those early morning workouts can lead to “the bonk,” which happens when your body runs out of glycogen. If you’ve ever felt like you’ve lost the ability to push your aerobic envelope and felt like you’ve hit a wall. That’s the bonk.
Bonking is not one of those “good pain” times, but it will inevitably happen to you at some point. When it does, don’t try to push through. Instead, cut your losses and get on the recovery program by eating, resting, and then reevaluating your eating schedule and choice of workout times.
If exercising when your glycogen stores are low (e.g., in the morning) is the only time of day available, you can fix the situation nutritionally. Eat a half (or even a whole) banana, or have a cup of watered-down juice before you work out, helping to boost glucose levels in your blood. Making it less likely you’ll tap into your glycogen stores. Alternatively, you can try to top off those stores by adding an extra serving of complex carbohydrates to your evening meal. If neither strategy works (you’ll know if it doesn’t — bonking isn’t subtle), that means you’re on a nutritional edge, and you aren’t eating enough total daily calories to recover from your workouts. It’s time to reevaluate your daily caloric intake.
2. When your stomach is empty
Best for: Burning fat and losing weight
Best time: Morning
In the morning, before you’ve eaten, your body is more likely to tap fat stores for energy during aerobic workouts, and you can train your body to become more efficient at doing so. You’re also “burning fat,” which sounds even cooler. While fantastic in theory, it’s not so fun in practice if you force your body into a situation where you bonk.
- Bonking is more likely to occur when you train at a very high intensity, run, or cycle for a very long distance. Low-intensity workouts can have added benefits if done in the morning on an empty stomach.
- If that lower-intensity morning workout is a strength session, taking additional nutritional steps can help optimize recovery.
Your body doesn’t store protein, so if you strength train before you “breakfast,” you’ll put your body into a catabolic (breakdown) state, which, as you might imagine, is less than optimal for building muscle. Fortunately, it’s easy to reverse the situation: have a protein shake or a protein-rich meal within a half-hour of completing your workout.
Two additional weight-loss advantages of an AM workout:
- It can decrease your appetite and inspire you to be more physically active throughout the day, according to a study at Brigham Young University in Utah.
- Sweating early in the day can improve the duration and quality of your sleep later on, according to researchers at Appalachian State University. That’s important because adequate sleep (more than 8 hours a night) is associated with more significant fat loss if you’re trying to slim down.
3. When your body temperature peaks
Best for: Building strength
Best time: Late afternoon/evening
- Wait at least an hour after waking before you start pumping iron or doing exercises that require you to flex your spine (e.g., crunches), especially if you suffer from back pain.
- If you can wait to work out until later in the day, all the better.
Your body temperature drops while you sleep, which is one reason you might wake up stiff and lacking flexibility. The discs between your vertebrae also fill with fluid as you slumber, making them more susceptible to injury first thing in the morning.
Your body temperature climbs throughout the day, peaking between 4:00 and 6:00 PM. As it rises, so too does muscle strength and power, according to a study in the Scandinavian Journal of Medicine & Science in Sports. What’s more, Scottish researchers report that exercise-induced increases in testosterone production are highest in the late afternoon and early evening.
If you’re looking to maximize strength gains, it’s best to schedule your workout for after work, or even during your lunch hour, rather than trying to cram it in before you leave for the office. But there’s always a “but,” and in this case, it has to do with a principle known as “temporal specificity,” which states that your body will adapt to be strongest at the time of day during which you usually train. So while you might initially benefit from late afternoon strength workouts, you’re better off scheduling those workouts for (you guessed it) whenever they’re most convenient for you.
Is It OK to Exercise Before Bed?
- Exercise requires a lot of nutrients, which are further depleted at night.
- Working out directly before bed can affect your sleep.
- Unless it’s is the only time you’ll work out or the only time you feel the best, you should probably avoid it.
Most people have a hard time getting to sleep after a workout because exercise can throw off your melatonin, the hormone that regulates sleep, among other things, which isn’t ideal because sleep is essential for recovery. It’s when your body naturally produces most of its own performance-enhancing drugs in the form of hormones. If possible, eliminate anything that hurts your ability to sleep.
There’s nothing inherently wrong with training at night. If you’re on a strict diet, perhaps trying to lose weight, you run a further risk by training and then not eating to recover from the workout before bed. If you’re on a low-calorie diet and plan to train hard at night, you should follow your workout with a nutritional recovery strategy, such as an overnight protein/casein supplement or small meal before going to sleep.
The bottom line is that everyone’s body responds differently. We all need to exercise, and most of us could eat better. In between are a lot of individual variables. When it comes to getting your best possible workout, psychology often trumps physiology. Exercise when you can and pay close attention to your performance. Then choose your preferred workout time based on your results. It’s that simple.