Hydration for Kendoka: An Overlooked Tool for Performance

Have you ever felt more exhausted than you should halfway through keiko, struggling to keep your technique sharp and your energy up? Or maybe you've stepped into a shiai feeling sluggish and slower than usual, wondering why your body isn't cooperating?

Troubleshooting this could involve testing and retesting a variety of things, one of which could be your hydration status.

Why Hydration Matters in Kendo

Kendo is intense.

Each session demands bursts of explosive power, precise technique, and unwavering mental focus. Even slight dehydration can impair these critical components, leaving you tired, less coordinated, and mentally foggy.

By the time you're noticeably thirsty, your performance has already been compromised.

Hydration directly influences muscular endurance, reaction speed, and overall power. Studies show that just a 2% loss in body water can significantly reduce strength, endurance, and reaction time (all qualities that you hopefully value!).

You might liken hydration to an internal battery. When it's fully charged, you can move explosively, think sharply, and recover quickly. But when the battery drains and you lose body water without replenishing it, everything slows down, and your performance crashes. Sometimes that feeling is just from being downright exhausted towards the tail end of a hard practice. Some of you though, it really is a lack of awareness to the role that hydration plays in facilitating sport performance.

Kendo involves strategic thinking, sharp reflexes, and quick decision-making. Dehydration negatively impacts all these cognitive functions. Proper hydration ensures you're mentally alert, helping you read your opponent better and react faster. 

Easy, actionable tips to ensure you're optimally hydrated:

• Check your urine color:
• Aim for a pale yellow.
• Dark urine = dehydration; completely clear = maybe over-hydrating.
• Drink Before You’re Thirsty: Aim to drink about 500ml (16~ ounces) of water 1-2 hours before practice. (Pro tip: this isn’t chugging a Dasani bottle. This is consistent sipping up to this point. Keep in mind, hydration starts from the moment you wake up. No amount of Pocari Sweat (Gatorade) drank during practice will catch you up for not going into practice already in a hydrated state.
• During Practice:
• Aim for 150–250 ml every 15–20 minutes.
• If it’s super intense or hot, consider adding electrolytes after the first hour.
• After Practice:
• Weigh yourself before and after if possible, if you want to approach this like a pro would.
  Replace about 1.5x the amount of weight lost (example: lost 1 kg? Drink ~1.5 liters).

Because kendo is explosive and sharp (not slow endurance like marathon running), electrolyte balance is a bit more important than just pure water. Having an electrolyte drink ready after the first 60 minutes can really come in clutch. (and for some of those crazy 4+ hour godo-keiko’s, I personally would even add a ‘clear whey’ protein to my sports drink for other good reasons than hydration.) 

Small hydration habits can lead to noticeably better practices and overall health. By simply paying closer attention to your hydration, you can enhance endurance, sharpen your mental focus, and better manage your health and weight.

It flows from proper hydration! You can do a lot of other things right in the realms of sleep, nutrition, and recovery, but dehydration will shut you down. Athletes often feel frustrated when they “hit a wall,” but from an evolutionary standpoint, the body is prioritizing survival over your competition goals. Dehydration is one of the first and fastest triggers of this protective slowdown.

Good luck! Happy training

(Bonus: message me on instagram for a homemade sports drink example if that’s interesting to you. I know I don’t always like to buy a $4 Gatorade before practice.)