Is it Better to Do Cardio in the Morning or at Night?

Is better to do cardio in the morning or at night? I’ve talked fasted training in the past. Fasted cardio is often done in the morning, which could lend itself to AM cardio being the favorite. Fasted HIIT may be best for those who already lean and looking to shed additional bodyfat. What about for those aren’t already lean and who aren’t fasted? Luckily, scientists from the Sports Medicine Research Center and the Department of Sports and Exercise Medicine at the Tehran University of Medical Science recently conducted a study that took a look at whether it is better to do cardio in the morning or at night.


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Is it Better to Do Cardio in the Morning or at Night?

Study authors considered whether or not the often-cited increase in fatty acid oxidation with morning training (done in the fasted state) could be irrelevant compared to the effects of early exercise on (inactive) subjects’ appetite and food intake within a given 24 hour period.

The researchers did point out that “there are few studies that consider the effect of a single session of exercise at different times of day on appetite or food consumption”. Many – and I mean many – people cite a lack of time as a reason for not getting their workouts in. With this in mind, the study’s authors also suggest that “exercise should be undertaken at the best time of day in order to obtain maximal appetite suppression and greater weight loss.”

Study Method Overview

To figure out whether it is better to do cardio in the morning or the evening they conducted a 6-week study comparing the effects. Inactive female participants were chosen “to eliminate the effects of other types of exercise on outcomes” and “to decrease the risk of musculoskeletal injuries during exercise testing and prescribed aerobic exercise.”

Morning aerobic training sessions occurred within 8–10 AM, while the other subjects had to complete their workouts between 2–4 PM. Each workout included 30 minutes of running on the treadmill. Participants went at a pace where they could no longer talk to someone without breathing heavily.

Participants recorded their food 24 hours before and after exercise sessions and filled out an appetite visual analogue scale to estimate food consumption, fullness, hunger, satiety, and cravings before the exercise session and 15 minutes after at baseline, and in the third and the sixth week of the trial.

Study Results

Researchers found that the morning cardio group might have a weight advantage. Subjects in both groups burned the same amount of energy during their workouts and didn’t have different post-workout appetite scores. However, the effects on the subjects’ energy intakes differed significantly.

The subjects in the morning cardio group consumed -17% less food (energy) with most of the reduction coming from carbs.

However, there wasn’t a significant change in body composition because the method used was fairly unreliable – they used a body composition analyzer from Jawon Medical Co. Ltd. This analyzer measured lean mass and fat mass data. If the researchers had chosen to focus on the skinfold data to assess changes in body fat, there was a significant difference between the groups.

  • There was an increased reduction in ab skinfold thickness in the morning cardio group.
  • There was an increased reduction in suprailiac (near the hip) skinfold thickness in the evening cardio group.

The short duration of the study (6 weeks) is one of its weaknesses, but the way in which the body composition changes were measured are a weakness as well.

Key Takeaway:

For both groups, the energy you spend during cardio is often not fully compensated later in the day.

Cardio in the morning may have an added bonus that it actually reduces your potential food intake and could result in an overall greater reduction in body weight.

More research is needed to confirm the results of this study. Using DEXA scans, widely considered today’s most reliable method of body composition measurement, and blood work can help determine whether or not it is truly better to do cardio in the morning or at night.

It “appears that moderate- to high-intensity aerobic exercise in the morning could be considered a more effective program than evening exercise on appetite control, calorie intake and weight loss.”

So, all that being said, do your cardio in a time that suits you. If you enjoy your morning workouts, then be aware you may have an added bonus in getting after it in the AM!

Do you do your cardio in the morning or at night?

When is the Best Time to Do Cardio? Morning or Night?


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