Karate tournaments are typically long, exhausting affairs. The combination of nerves, a poor sleep the night before, a long and unpredictable day, and the actual competing itself, can all be incredibly draining.

It’s so tempting—and easy—to reach for that caffeine to perk you up. But should you? Will that cup of coffee in fact help or hurt your performance? How much is too much?

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Caffeine Can Boost Performance

It turns out that small to moderate doses of caffeine can improve our performance. For most people, around 3-5 mg of caffeine per kg of body weight can boost performance without any risk to our health, up to a maximum of around 400 mg per day.

So for example, I weigh around 50 kg. The ideal range for enhancing my performance works out to between 150 and 250 mg of caffeine per day. For those of you who can’t do math:

  • Ideal range is 3 mg/kg to 5 mg/kg per day.
  • Individual weighs 50 kg.
  • 3 mg/kg x 50 kg = 150 mg of caffeine.
  • 5 mg/kg x 50 kg = 250 mg of caffeine.
  • Ideal range for a 50 kg individual is approximately 150-250 mg of caffeine per day.

For reference, a 16 oz (473 mL) cup of coffee clocks in at around 200-250 mg of caffeine, depending on the brew. So for me, at 50 kg, that would be my upper limit: I wouldn’t want to have more than 16 oz (473 mL) of coffee per day for the best result.

Best Time to Consume Caffeine

And the ideal time for that hit of caffeine? Approximately 30 to 60 minutes before exercise. At around 30 minutes you will feel the effects of that caffeine, but it’s not until around 60 minutes after consumption that blood levels of caffeine will be maximized. So if I’m at a tournament, and my sparring division is coming up, and I’m feeling really run down, having caffeine at least 30 minutes—but ideally about 60 minutes—before my division can enhance my performance in the ring.

Individual Differences in Caffeine Tolerance

But how much caffeine should I have before my division? Well, it all depends. Individual and genetic differences do come into play here, and affect our tolerance to caffeine. I am a coffee and tea drinker, but I am sensitive to caffeine, so I need to be careful with how much I ingest in one sitting, and the time of day at which I ingest it, if I hope to sleep at night.

Theoretically, I can safely have up to 250 mg in order to enhance my performance, but if I have my whole caffeine allotment for the day all at once, even if one whole hour before my division, I will most likely feel like crap during my sparring match. Too much caffeine is hard on my stomach, makes me anxious and jittery, gives me facial flushing, gets my heart racing, and gives me nasty dry mouth. So I need to go with a much lower dose.

If your body does tolerate caffeine, be willing to experiment to find out the optimal amount for you. And preferably do this before that tournament, rather than for the first time on the day itself. It would be terrible to discover you have an intolerance to certain levels of caffeine right in the middle of your sparring match. If you find that you are sensitive to the effects of caffeine, stick with small doses, spread it out throughout the day, or skip it altogether. Figure out what works best for you.

Caffeine and Dehydration

And if you’re worried about that cup of coffee dehydrating you? Well, if you’re sticking with the recommended 3-5mg/kg per day, turns out you don’t need to worry too much. Caffeine is a diuretic—it does make you pee more often and lose fluids—but this seems to happen moreso with higher amounts, particularly at the 5-6 mg/kg range. At lower doses this doesn’t seem to be an issue. So you won’t need to worry about dehydration if you stick with small to moderate amounts of caffeine before exercise.

Bonus: if you are a regular caffeine user, your body adapts to your intake, so that the water from your coffee or tea isn’t lost in your urine. So IF you’re a regular user, you can count that cup of coffee towards your fluid intake for the day. If you’re not a regular caffeine user, those infrequent doses of caffeine will probably affect your hydration level, so you’ll want to make up for it with extra fluids.

Small to Moderate Amounts are Best

So that’s it! Next time you’re at your karate tournament, and are feeling droopy and wanting a performance boost, you will probably be okay with a hit of caffeine about an hour before your division. Just keep your intake small to moderate, and stick with an amount that works for you.

(For more information on caffeine and performance, check out the article by Precision Nutrition listed below under Recommended Resources.)

Have you experimented with caffeine to boost your performance in the ring? How has that worked for you? Feel free to share your experiences in the Comments section below.

Recommended Resources

Learn more about caffeine and athletic performance here.