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Early morning workout v late night workout

Early bird or night owl – depending on your fitness goals, both have their advantages…

Written by Becky Hardy
Published 19.04.2023

Whether you work out late at night or early in the morning, it’s important to know that both fitness habits have their advantages and disadvantages.

Depending on your training goals, these pros and cons could be significantly impacting the efficiency of your workout.

Sports nutrition experts Bulk have weighed up the benefits and drawbacks of an early morning workout versus a late-night workout – highlighting which is best depending on the fitness results you want to achieve.




  • Increased alertness
  • Can improve weight loss rate
  • Improves your body clock
  • Helps with appetite control



  • Less time to warm up before weightlifting
  • Lack of sleep
  • Inability to build muscle
  • Metabolic rate can impact eating habits

Advantage: Increased alertness

Believe it or not, one of the biggest advantages to an early morning workout is feeling more alert.

While you may feel exhausted as you drag yourself to the gym before the sun’s up, your body produces a hormone called cortisol which is at its peak level around 8am.

Cortisol, also known as “the stress hormone”, helps you keep awake and alert. This hormone will only cause you problems if there is either too much or too little of it.

If you have a healthy circadian rhythm – the 24-hour cycle that includes physiological and behavioural rhythms like sleeping – your body will be more primed to exercise early in the morning.

Advantage: Can improve weight loss rate

For those looking to shred some body fat, a big advantage of working out in the morning is that it’s generally better for weight loss.

Elevated cortisol levels and growth hormone in the morning are both associated with your metabolism.

Therefore, taking high intensity exercise in the morning can help to boost the metabolism and burn more body fat, drawing out more of your energy from your fat reserves.


Advantage: Improves your body clock

A study published by the Journal of Physiology found that exercising at 7am can shift your body clock earlier.

Not only will this improve how alert you feel in the morning, but it can also prime you to fall asleep easier and earlier that evening: allowing you to get enough rest to wake up and repeat the same routine again the following day.

Advantage: Helps with appetite control

Exercise generally helps to control your appetite.

Studies have now shown that aerobic exercise – like running, cycling, and swimming – decreases appetite. This is because it alters our hormone levels that drive hunger.

The theory behind exercise as a suppressant or stimulant of your appetite is based on the activities of two main hormones: ghrelin and peptide YY. These are hormones with opposing actions, both released during different forms of exercise. Ghrelin stimulates appetite while peptide YY decreases appetite.

As aerobic exercise suppresses the ghrelin hormone, this will help you to control your appetite.

Disadvantage: Less time to warm up before weightlifting

For those wanting to build muscle or tone up, an early morning workout could do more harm than good.

Our bodies need time to warm up before lifting weights. If you don’t give your muscles enough time to loosen up, you could risk an injury.


Disadvantage: Lack of sleep

If you didn’t get to bed early enough the night before, or perhaps had a restless sleep, getting up at the crack of dawn and working out could be straining to the body.

Ensuring the body is fully rested before engaging in any workout is extremely important.

If you worked out the night before, sleep is what allows muscle tissue time to recover between workouts.

Having enough sleep is also important for having the energy to exercise. Not getting enough sleep can lead to being less physically active during the day and reduced muscle strength during workouts.

Disadvantage: Inability to build muscle

Working out first thing in the morning generally doesn’t help with building muscle.

This is because your body needs a few hours to refuel stores that it has used up during the night.

Your muscles primarily use glucose to fuel weightlifting and resistance exercises. A morning workout doesn’t result in significant gains in either muscle mass or strength, as you don’t yet have sufficient stores.

Therefore, if boosting muscle or strength are your primary goals, workouts will see more benefits later in the day.

Disadvantage: Metabolic rate can impact eating habits

As an early morning workout will boost your metabolism early in the day, your metabolic rate then generally slows down again in the evening.

Whereas an afternoon or evening workout will boost your metabolism later in the day – which is more beneficial if your dinner is your main meal, providing the most calories.

For those looking for results in weight loss or weight maintenance, ideally you want to align your workouts with your biggest calorie intake to ensure best results.

If you want to burn calories and fat, changing your workout routine to the time of day when you eat your largest meal could be extremely beneficial.



  • Higher energy levels
  • Muscles will tone up faster
  • Negative impacts on sleep is a myth
  • Effective stress relief



  • Can impact consistency
  • Post-workout fuel is consumed too late
  • Less time for post-workout stretching

Advantage: Higher energy levels

A study from The University of Birmingham shows you can work out for up to 20% longer when exercising in the evening, at a higher intensity.

It goes without saying, then, that workouts at a longer, faster, stronger rate will demonstrate results a lot quicker.


Advantage: Muscles will tone up faster

Muscle strength and function peaks in the evening, as fluctuating hormones can make workouts later in the day more effective.

High levels of cortisol in the morning can prevent muscle growth, however high levels of testosterone in the evening boosts it.

Advantage: PM workouts having a negative impact on sleep is a myth

Whilst many people believe that working out late at night can be disruptive to your quality of sleep because endorphins are still buzzing, this is a myth.

Endorphins actually help to improve the ability to sleep, which also helps reduces stress.

A study in Sleep Medicine found that only 2% of vigorous exercisers said workouts interrupted their sleep, while 30% slept better after a good sweat.

Of course, depending on how late night your workout is, people may tend to rely on caffeine and taurine, which are known as popular pre-workout supplements.

Whilst there is a lot of research to support its performance benefits, particularly if you’re strength training, caffeine can be problematic and impact sleep quality.

Therefore, opting for caffeine-free pre-workout fuel is a better option; those containing Beta Alanine and Citrulline Malate help to preserve muscle pH and acidity levels, delaying the build-up of lactic acid and muscle fatigue.

Advantage: Effective stress relief

After a long day, exercise can help you unwind and de-stress.

This is because physical activity produces endorphins, which are chemicals in the brain that act as natural painkillers.

Studies show that among those who exercise, 33% of high-stress adults said they feel less stressed after exercising, compared with 18% of low-stress adults.

Disadvantage: Can impact consistency

Exercising later in the day can make it much more tempting to move it to push back your session into tomorrow whenever you feel tired.

Studies also suggest that fixing your workout session to mornings may make it easier for you to turn exercising into a daily habit.


Disadvantage: Your post-workout fuel is consumed too late

It’s important to help your muscles recover to replace their glycogen stores.

Eating a meal which contains both carbohydrates and protein after your exercise session is always recommended.

However, if you’re completing a workout late at night, your hunger levels may take a lot longer to kick in, meaning you’re eating extremely elate.

Eating late at night goes against your body’s circadian rhythm, impacting your metabolism and making it more difficult to maintain blood sugar levels.

Disadvantage: Less time for post workout stretching

You may be going to the gym at 9pm, but if it closes at 10pm then you’ll likely be rushing out of the door.

Muscles and tendons that aren’t stretched properly after exercise may be more susceptible to injury.

It’s not only important to make sure you’re stretching after exercise, but also that you’re doing the right types of stretches. Bulk.com experts recommend using the RAMP method to help structure your workouts.

Following these steps for a warm-up which should last around 15–20 minutes should put you in an optimal state to carry out your workout.

The research in this article was conducted by bulk.com – a business founded on the belief that sport, health, fitness and nutrition are for everyone, no matter who you are, what you do, or how you do it

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