What’s the best time of day to work out – before or after work?

If you’re like me or most of my clients, one of the biggest challenges when it comes to exercise is fitting it around your work. Which often raises the question – should I work out before or after work? In this blog, I’ve pulled together evidence from many different studies to try to answer that.

By looking at how morning, afternoon and evening workout sessions impact our body and brain, I’m going to try to help you to know whether a pre-work or post-work WOD will help the most with your long term goals.

Benefits of exercising before work


Exercising in the morning has been linked to improvements in both the length and quality of sleep. Morning exercise also seems to play a positive role in the length of REM sleep, which is thought to be beneficial for emotional processing, memory consolidation and cognitive function – keeping your thoughts and feeling positive. If getting better sleep is one of your goals, getting to the Box before work should be a key part of that [1].

Attention & Concentration

While exercising at any time of the day improves attention and concentration, concentration levels tend to be higher in the morning. This means that adding exercise to your morning allows you to tap into improved concentration and attention at work, rather than activating your concentration in the evening, when it’s probably time to chill [2].

Keeping Calm

You may already know that your nervous system is divided into different branches, including the sympathetic nervous system (often known as the ‘fight or flight’ mode) and the parasympathetic nervous system (often known as the ‘rest and digest’ mode). Exercise before work has been found to increase the parasympathetic nervous system, meaning you are more relaxed by the time that bedtime comes around. Not only might this explain some of the improved sleep you get from working out before work, but it might also add to you feeling calmer in general over time [3].

Benefits of exercising after work


Sports performance typically peaks in the afternoon. And as the day progresses, your slightly higher body temperature may also be linked to improved flexibility. If you are pushing for a PB or to set a great time in the WOD, an after work workout might give you the edge that you need. [4]

Insulin Sensitivity

Insulin resistance is a condition now thought to play a central role in many chronic health issues – from weight gain to high blood pressure, type 2 diabetes to heart disease. Reversing insulin resistance (increasing ‘insulin sensitivity’) can be achieved by increasing exercise and limiting the sugar and carbohydrate in your diet. Studies have shown that afternoon and evening workouts are the best for improving insulin sensitivity, making a post work WOD the preference for those wanting to lower their risk of type 2 diabetes, reduce their blood pressure or protect their heart. [5]

What about weight loss?

A common reason for many people to work out is to burn body fat and develop a leaner, more muscular physique. But is there a clear winner when it comes to the best time of day to work out in order to burn fat.

Despite a few studies looking into this, the time of day you work out doesn’t seem to have an impact on how much weight you lose or how much body fat is burned. So if losing body fat is one of your goals, it shouldn’t impact you when you work out. [6]

On the subject of burning body fat, it’s important to be aware that what we put in our mouths can be just as important as how hard we work our bodies – with daily doses of sugar, carbohydrates and chemicals (the kind your find in ‘diet’ fizzy drinks) all capable of blocking your body’s ability to burn fat for energy. And so it’s important to have a diet that you find tasty and sustainable, else you might end up gaining back any weight that you burn in the Box. [7]

Final Thoughts

On the whole, the evidence seems to suggest that a pre-work WOD might be the best for your brain, with benefits in sleep, attention, concentration and calmness. But a post-work WOD might have the edge when it comes to your body, with benefits in physical performance, flexibility and improved insulin sensitivity.

But I really want to add that exercise at any time of day is so much better for your brain and body than no exercise. So while I hope that this blog is interesting and helps you with your long term goals, please don’t miss any sessions because of this information. If in doubt, head to New Horizon Crossfit and workout, whatever the time is!

About the Author

Ryan Parke is The Men’s Coach – a TEDx Speaker specialising in how hormones, lifestyle and goal setting impact male mental health. Ryan works with industry leaders, charities, and NHS Trusts who want to provide effective support to men. His 90-day coaching programme helps men to improve their mental health by using science-based strategies to achieve their life goals. Ryan has been a member of NHC since 2022 and prefers to work out in the mornings.

1. R1063: Y Yamanaka et al (2015). ‘Morning and evening physical exercise differentially regulate the autonomic nervous system during nocturnal sleep in humans.’ American Journal of Physiology.
2. R1062: R Maeneja et al (2022). ‘Cognitive Benefits of Exercise: Is There a Time-of-Day Effect?.’ Healthcare.
3. R1063: Y Yamanaka et al (2015). ‘Morning and evening physical exercise differentially regulate the autonomic nervous system during nocturnal sleep in humans.’ American Journal of Physiology.
5. R1065: R Mancilla et al (2020). ‘Exercise training elicits superior metabolic effects when performed in the afternoon compared to morning in metabolically compromised humans.’ Physiological Reports.
6. R1067: P Brooker et al (2022). ‘The efficacy of morning versus evening exercise for weight loss: A randomized controlled trial.’ Obesity.
7. R1051: T Noakes (2019). ‘IT’S THE INSULIN RESISTANCE, STUPID: PART 1.’ Crossfit.com.

people working out in a group fitness class


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