Training tips : Hydration Rules, OK!
It would appear that most of Europe and the US are experiencing very high temperatures and humidity levels at the moment, weather which is energy sapping at best, but downright dangerous at worst. This is particularly so for runners, for whom access to fluids or respite from heat can be hard to come by, especially on a long run.
Most runners know that staying hydrated is key when exercising. The body sweats water to aid in cooling in order to maintain body temperature. If you become dehydrated, this cooling effect is minimised, or can even stop, which puts you into real danger. Taking in too little water risks the dangerous effects of heat exhaustion or heat stroke.
However, this doesn’t mean that you should chug pints, gallons, bathtubs of water before running on hot days. With everything, too much of a good thing is always a bad idea. Too much water and you run the risk of hyponatraemia, an extremely dangerous condition whereby excessive water intake causes an imbalance in electrolyte levels, due to dilution of the blood and corresponding lowering of sodium levels. Some common symptoms of hyponatraemia include nausea and vomiting, confusion, fatigue, muscle weakness, spasms and cramps, however extremely low sodium levels can cause seizures or coma.
In light of this, it was timely when the other week Runners World released some advice, busting 8 of the most popular ‘myths’ about hydration, which I have paraphrased below. Please do read their full article for the full information.
1) Drink eight glasses of water a day – You do need regular hydration top ups, but how much is an individual thing. Many people cannot drink eight glasses of water a day, while larger people or those who are active may require significantly more. Eight glasses a day is a guide, and unless you have a specific need then often letting your thirst guide you is sufficient.
2) You need to pee clear to be hydrated – Well, urine that looks like water is a bit over the top – it means you are literally full up and your kidneys are just dumping it out. Note: this can lower the ability of your kidneys to filter your blood if they are too busy just chucking out water. A normal rule of thumb is pale yellow like straw, or maybe easier to imagine, a light white wine. However, if your urine is dark, or cloudy, or particularly smelly, you should really increase your hydration levels. Urgently.
3) Caffeine dehydrates you – To a point, yes. But normally for only a few hours after consumption, and there is a mechanism in the body to aid water retention during exercise which, according to the Runners World article, negates the impact of the caffeine. So if you use caffeine as a performance boost, just make sure to watch your hydration levels as you exercise and you should be fine.
4) Thirst isn’t a good indicator of hydration – This one is another which is largely untrue. General consensus is that if you’re thirsty, you’re already dehydrated. However, this shouldn’t be your only guide. If your pee is still light yellow you are probably fine. People who sweat a lot, or are doing long periods of exercise, may need to do some more homework and figure out their rough ‘sweat rate’ so they can factor this into their calculations of hydration rates. However, no one should try to replace more fluid than they lost through exercise, this can lead to hyponatraemia.
5) Pure water is best for hydration – Water is a great way to hydrate, but not if you’ve lost a lot of salts through sweating. Consider using an isotonic sports drink instead, as the electrolytes present will help raise your salt levels with your water, stopping you from peeing it out.
6) You can’t drink too much – Wrong! Too much water can lead to hyponatraemia and is as dangerous as heat stroke if left untreated. Listen to your thirst and don’t drink to a schedule.
7) Drinking lots of water is a good way to “detox” – Hmm. The best way to detox is just to put less toxins into your body. Excessive water consumption can alter your sodium levels (see hyponatraemia above) and if your kidneys are working too hard to push water, then they aren’t doing as much filtering either.
8) Staying hydrated eliminates your risk of heat stroke – Heat stroke is life-threatening if your temperature goes beyond 40.6 degrees C (105 degrees F) as the body’s thermoregulation mechanism breaks down, and just stops. Dehydration is a causative agent, as it leads to heat exhaustion, the precursor to heat stroke. However, no amount of hydration can eliminate the risk. Heat stroke is caused by the body’s inability to shed excess heat. High temperatures, excessive activity, high humidity levels can all tip the balance towards constant heat build-up, and none of these can be changed by a high level of water intake.
So, what do we runners need to do then? Pay attention to the above 8 items, stay hydrated, run when it is a bit cooler, and most importantly pay attention to your body. If you don’t feel right, then you aren’t right. Instead, stop running, seek cooler temperatures or the shade and decide if you are hydrated enough (drink more), or if you’ve been guzzling and are over hydrated (try a salt tablet to raise your sodium levels).
Safe running in the heat everyone!
Get Going, Get Running!
Related article: Runner’s World – 8 Hydration Myths Busted