How Does Caffeine Affect Your Workout?
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How Does Caffeine Affect Your Workout?

Caffeine is a go-to performance enhancer for many athletes who use it to improve both physical and mental performance during their workout. It can provide a useful boost to training sessions, but it’s not for everyone. If you’re thinking of introducing caffeine to your gym sessions you need to consider how and when to consume it.

How does caffeine work?

Caffeine is a Central Nervous System (CNS) stimulant. The CNS consists of the brain and spinal cord and is responsible for controlling most functions of the body and mind [1]. By stimulating the CNS you feel more alert, focussed and energetic. It can improve your mental performance and motivation, too.

Consuming caffeine also:

  • Affects your hormones by increasing the circulation of epinephrine (adrenaline). This is the “fight or flight” hormone. Adrenaline raises your heart rate, which will then increase the amount of blood pumping around the body and supply more oxygen to your muscles [2].
  • Has been shown to enhance dopamine levels, which plays a role in how we feel pleasure [3].
  • Is a diuretic, making you need to use the bathroom more often.
  • Increases your blood pressure.
  • Releases acid in your stomach, sometimes leading to an upset stomach [4].

Many sources suggest most healthy adults can drink between 300-400mg per day of caffeine with little evidence of health risks. In fact, studies have found coffee drinkers in particular have a reduced risk of illnesses including type 2 diabetes, liver cirrhosis, liver cancer and depression. However, every individual will have a different tolerance level for caffeine. Short-term symptoms of excess intake include restlessness, anxiety, dizziness, upset stomach, irritability, insomnia, a fast heartbeat and tremors.

The impact of caffeine on your workout

Provided you are having the right amount of caffeine for your body and tolerance level, it can be a useful performance enhancer when you need it. Having caffeine before a session can make you feel more motivated about training, prompting you to push yourself that bit further [5]. The impact on dopamine levels can also improve your mood and enhance your “exercise high” after working out.

Will caffeine make me stronger?

Caffeine is one of the most researched substances and it is reported to help athletes enhance their performance, train longer and harder.

But the evidence specifically on caffeine’s impact on strength is mixed. Most of the studies will cite a small improvement. However, it is likely due to the effect caffeine has on the CNS, which makes exercise seem easier and less painful. This generally means that people try harder and push themselves further [6]. Caffeine will not drastically boost your lifts in one session, but it could help you get that extra bit of output on a heavy lift, incrementally improving your progress over time.

It’s also important to remember that most caffeine beverages contain calories. If you are trying to reduce your calories, you’re better off opting for a black coffee instead of a latte with sweet syrups, as this will affect your daily calorie intake.

How and when should I have caffeine before a workout?

The effects of caffeine are often noticeable after about 15 minutes but will reach peak levels within 30-60 minutes of consumption [7]. This means having caffeine around an hour before your workout will allow it to take full effect. Of course, the rate you have it will play a role too. For example, if you are slowly sipping on a large flat white this will take longer than if you use a caffeine pill.

How much caffeine you need to feel the effects will depend on your personal sensitivity to it. However, at Plexus we find between 100-200mg is enough for the average person, which is equivalent to roughly one or two coffees.

We’ve established that caffeine can be useful, but that doesn’t mean it’s essential. At Plexus, everything we do is about building a healthier, balanced and more enjoyable lifestyle. We would only encourage our clients to time their coffee before a session if it’s something they already enjoy and they feel they could use a little extra boost. This could be due to a poor night’s sleep or especially tiring day at work.

It’s also important to prioritise rest. Caffeine’s half-life is five hours. This means that after five hours you will still have half the amount of caffeine you consumed in your system. If you’re planning an evening workout, it’s best to skip the coffee. Otherwise, you may risk compromising getting a good night’s sleep. Getting enough quality sleep will improve your motivation, performance and results far beyond what a caffeine boost can provide. If you’re wondering how much sleep you should be getting, read our article here.

Should I have preworkout?

Preworkout just isn’t necessary if you are primarily strength training to improve your overall quality of life.

The main ingredient in most preworkouts is caffeine, but it’s at a much higher dosage than a coffee. Many can contain up to 400mg caffeine, which is equivalent to four coffees [8]. For most people, this is likely to result in overconsumption and they may feel jittery, anxious and have a disrupted sleep.

There’s also very little consistency in the ingredients used in preworkouts and plenty of unnecessary chemicals. Amino acids, B vitamins, creatine, artificial sweeteners and other chemicals regularly appear on the ingredients list, but quantities can vary greatly. Preworkout is also often expensive. Unless lifting the heaviest possible weight is one of your main priorities in life, you’re better off just having a coffee. It’s going to be more enjoyable and contain a more suitable dose of caffeine.

The verdict

Caffeine boosts your training and is safe for most adults to have before a session, provided you are not overconsuming it and it’s affecting your sleep. Having a low to medium caffeine dosage one hour before a workout may help you push that little bit harder.

However, caffeine is not an essential part of your training regime and should not come at the expense of other aspects of your life. It should only be introduced because you enjoy it, or used to provide an extra boost when your energy levels are low. If you’re training in the evening, it’s best to avoid caffeine. It’s more important that you prioritise a restful night’s sleep, which will lead to a more balanced, happier lifestyle.