Morning workouts, anyone? I see myself as one of the self-righteous people who get up early, downs a cup of coffee, and immediately must get her cardio session in, or my whole day is unproductive. Something about getting your heart rate up early in the morning feels right. I immediately see butterflies and rainbows all around me, and I get a good pump of energy.

I was surprised to find a research study that found, exercise in the afternoon produces a superior metabolic effect than morning exercise (1).  Then I came across another study that found the body’s temperature rises throughout the day and peaks in the afternoon (2).  

Here’s why working out in the afternoon or early evening might be more beneficial then the morning workouts.

Higher Body Temperature

Human body temperature peaks in the afternoon, which means you’d be able to push harder in the afternoon (2). When the body temperature rises, scientists believe that muscle strength and cardiovascular endurance also peak.

Optimal Hormonal Profile

Our hormonal profile is optimal for muscle growth and strength in the afternoon. Testosterone, a hormone needed for muscle growth (4), is higher in the afternoon than in the morning. On the other end of the spectrum is cortisol, the stress hormone that isn’t optimal for muscle growth. The cortisol levels peak in the morning and then gradually decrease as the day goes on. So, exercising provides the perfect hormonal levels for optimal muscle growth later in the day.

Protein Synthesis Pikes

Protein synthesis pikes later in the day, which means that you can maximize your body’s ability to recover (1). Protein synthesis is affected by the circadian rhythm. Science proves that removing circadian input by exposure to either extended periods of darkness or light hampers muscle growth (5). Activity or resistance training later in the day promotes muscle protein synthesis at night (6).

Higher Glucose Levels

Exercising in the afternoon is metabolically superior to morning exercise because you aren’t in a fasted state. You’ve had breakfast and snacks. When you eat, your blood sugar levels go up. Sugar in the form of glucose is the fuel for higher intensity workouts. You will be able to push harder during your afternoon workouts. Exercising in the afternoon is more beneficial for skeletal muscle insulin sensitivity (1).

Increased Endurance and Power

Working out in the evenings can increase your physical capacity, aerobic capacity, and strength output (3). Exercise training in the afternoon induces a more profound increase in maximal power output (1).

The best time of the day to work out is when you can work out. But I’ve to say, after learning all the benefits of exercising in the afternoon, I’ll leave my speed training and hill repeats for afternoon sessions from now on when I may get more bang for my buck.

References-

1- https://doi.org/10.14814/phy2.14669

2- DOI: 10.1111/j.1600-0838.2010.01212.x

3- https://doi.org/10.1002/mus.20529

4-DOI: 10.1152/jappl.1989.66.1.498

5- https://doi.org/10.1073/pnas.2012450117

6- doi: 10.3389/fnut.2019.00017