Pre-Workout Timing: When To Skip It For Better Sleep

Pre-workout supplements can help boost energy, focus, endurance and strength during exercise, according to research. But they are not always a good idea. In some situations, they can do more harm than good.

Pre-workout is optional

Pre-workout is a dietary supplement, not an essential part of exercise. It is not suitable for everyone, and it is not designed to treat or cure any health condition.

If you are thinking about trying one, speak with your doctor first, especially if you:

Take prescription medicines
Are pregnant, trying to conceive or breastfeeding
Have a heart condition, high blood pressure, anxiety or sleep issues

A health professional can help you decide if the ingredients and dose are safe for you.

When timing matters most

In general, pre-workout is taken 20 to 60 minutes before exercise so the ingredients have time to take effect. The main concern is caffeine, which is one of the most common ingredients and is included to increase energy, focus and endurance.

‘It is best to avoid taking pre-workout late in the day or at night as the caffeine component may cause sleep disruption,’ says registered dietitian and personal trainer Nicolle Cucco.

Why late-day pre-workout can backfire

Most adults take around five hours to metabolise half the caffeine they consume. That is why many sleep specialists recommend avoiding caffeine for at least six hours before bedtime.

If you usually go to bed around 10 p.m., anything with a decent hit of caffeine after about 4 p.m. may still be in your system when you are trying to sleep. That includes:

A standard pre-workout scoop
Strong coffee or energy drinks
Other caffeine-containing supplements

If your workout starts after 4 or 5 p.m., it is often safer to skip the caffeinated pre-workout to protect your sleep. Poor sleep can undo many of the benefits you are chasing from training, including muscle recovery, hormone balance and appetite regulation.

Watch your total caffeine for the day

Dietitian and sports nutrition specialist Jordan Hill notes that timing is even more important if you have already had caffeine earlier in the day.

About 400 milligrams (mg) per day is the upper limit most healthy adults should stay under to avoid side effects like jitteriness, rapid heart rate, anxiety and insomnia.

To put this in perspective, that is roughly:

3–4 cups of brewed coffee, or
A combination of coffee, tea, soft drinks and a caffeinated pre-workout

If adding a pre-workout scoop would push you over 400 mg, it is a good idea to skip it.

The exception: caffeine-free pre-workout

Not all pre-workout products contain caffeine. Some formulas rely on ingredients such as amino acids, creatine or electrolytes instead.

‘For caffeine-free pre-workout supplements, there are no time constraints on when you can take them,’ Hill explains. If evening is the only time you can exercise and you still want a performance boost, a stimulant-free pre-workout may be a better fit.

You will still need to check the label carefully and clear it with your doctor, especially if you have kidney issues, heart disease or other medical conditions.

Safety tips for using pre-workout

If you and your doctor decide that pre-workout is appropriate, keep these guidelines in mind:

Start low and go slow. Begin with half the recommended dose to see how your body reacts.
Avoid mixing stimulants. Do not stack pre-workout with energy drinks, extra espresso shots or fat-burner products.
Stay hydrated. Many pre-workout ingredients are dehydrating, so drink water before, during and after your session.
Stop if you feel unwell. Palpitations, chest pain, dizziness or severe anxiety are all reasons to stop using the product and seek medical advice.

Dietary supplements are products intended to supplement the diet. They are not medicines and are not intended to treat, diagnose, mitigate, prevent, or cure diseases. Be cautious about taking dietary supplements if you are pregnant or nursing. Also, be careful about giving supplements to a child, unless recommended by their healthcare provider.