Some people insist that getting your workout done first thing in the morning is the key to successful weight loss. Other exercise devotees tout the benefits of sweating before bed. So, who’s right? Well, there’s plenty of research to argue both sides.
YOU’LL BE MORE PHYSICALLY ACTIVE DURING THE DAY
Some research suggests morning exercisers move more during the day, which is an important factor in weight loss. After all, physical activity accounts for 15–30% of your total caloric expenditure, according to a review in Medicine & Science in Sports & Exercise. Other research in Medicine & Science reveals that women who walked at a moderate-to-vigorous pace for 45 minutes in the morning were more physically active during the rest of their day.
YOU’LL EAT LESS
Cutting back on unnecessary calories is also critical for weight-loss success. The same study found that morning exercisers also consumed fewer calories throughout the day and were less tempted when they saw images of unhealthy foods.
YOU’LL KICK-START YOUR METABOLISM
Exercising first thing in the morning may wake up your metabolism and get your body primed for burning calories. “[Exercise] gets you from that sleeping, resting metabolic rate to a metabolic rate that’s a little more active,” says Jeffrey Potteiger, PhD, graduate school dean and professor in the department of movement science at Grand Valley State University in Grand Rapids, Michigan. Research in the Journal of Physiology suggests that if you if you exercise before breakfast, your body will tap into fat stores over carbs for energy.
YOU’LL SLEEP BETTER
Sleep plays a key role in weight loss. One small study in the American Journal of Clinical Nutrition found people who slept only four hours per night for five nights ate 300 more calories per day than they did when they slept nine hours per night. And most of those extra calories came from foods high in saturated fat. Research suggests exercise in general can improve sleep, and that exercising at specific times during the day can impact your sleep in different ways. While the National Sleep Foundation argues that exercising in the evening makes it difficult to fall asleep, researchers at Appalachian State University found college students who lifted weights at 7 p.m. were actually able to sleep through the night much better than both non-exercisers and morning exercisers.
YOU CAN GO LONGER AND HARDER
According to research in the journal Applied Physiology, Nutrition, and Metabolism, young men who performed intense exercise in the evening were able to go approximately one minute longer than morning (5.5 minutes versus 4.6 minutes). The evening exercisers also had a 7% higher anaerobic capacity or energy available to sustain intense, anaerobic exercise.
Considering there are potential weight-loss benefits to exercising in both the morning and evening, how do you know which time is right for you? As you’ve seen, there’s a bounty of research arguing both sides.
The answer: “The ideal time would be when it fits into that person’s schedule and it can become a regular part of what they do,” Potteiger says. After all, when it comes to weight loss, consistency is far more important than nit-picky details like which fuel source your body taps into for energy or how much higher your anaerobic capacity is in the morning versus the evening.
Looking to research studies for guidance is great, but as Potteiger points out, the findings of any given study may not apply to 100% of people. You have to do your own research to find the time that works best for your schedule and personal preferences. Consider the times of day when you feel most energetic and aim to exercise during those times. Alternatively, if you feel a dip in energy at a specific time (Think: mid-afternoon slump), think about taking an exercise break in place of your coffee break, Potteiger says. You may find you’re more productive when you return to your work.