Too much or Not Enough Water?

Ask cyclists how much and how often to drink during a long ride and you’ll get almost as many answers as there are cyclists. Some believe in reaching for the water bottle often and some drink more sparingly. Then there are those who follow a very strict regimen involving precise quantities of water consumed at regular intervals.

Who’s right?

That’s the question a team of researchers tackled in the review paper The Influence of Drinking Fluid on Endurance Cycling Performance.

Before delving into the findings, it’s worth noting that for many cyclists, a drink of cold water during a long, hard ride is more reward than part of a well thought out strategy to ward off dehydration and the decline in performance that accompanies it. But is relying on thirst to determine when to drink the best plan for cyclists who want to be the best they can be on their bike?

In an effort to get a handle on how much fluid cyclists should consume during rides of varying distances, the researchers waded through 151 studies before finding 15 that matched their nine-point criteria for inclusion, one of which included reviewing only those studies that looked at drinking no sooner than five minutes before getting on the bike. Their conclusions were based on the experiences of 70 cyclists in total, 10 per cent of them women.

The first noteworthy discovery is that for rides lasting an hour or less, cyclists should avoid draining their water bottle. Too much water during short, high-intensity bike rides has the potential to cause stomach upset such that it reduces performance by as much as 2.5 per cent when compared with no fluid intake.

“It has been demonstrated that above an exercise intensity of 70-75 per cent of Vo2 peak, gastric emptying becomes compromised and fluid starts to accumulate in the stomach, leading to abdominal bloating, gastrointestinal discomfort and reduced cycling performance,” said the authors of the paper published last month in Sports Medicine.

Some studies indicated that 50 per cent of the cyclists involved in short, fast rides suffered from stomach upset and overall discomfort after consuming too much water. It’s also worth noting that the majority of elite cyclists participating in 40-km time trials don’t reach for their water bottle. Instead, they tend to drink before a race, which allows fluids to be adequately digested before getting on their bikes.

As for rides longer than one hour, the researchers concluded that following a protocol as simple as drinking when thirsty improved performance similar to more regimented hydration protocols and resulted in better times than not drinking at all.

That said, there are a lot of variables to take into consideration when determining how much to drink during a lengthy bike ride.

“Both drinking to thirst and planned fluid intake are viable strategies and their use should be based on the cyclist’s preference, environment, course, type and duration of event, rules and opportunities to drink,” the research team said.

This seemingly sensible approach to deciding when and how much to drink is similar to that recommended to runners who, like cyclists, have been guilty of thinking that more water equals better performance. It’s also a reminder that cyclists shouldn’t follow the same hydration strategy every time they get on their bike — another bad habit that cyclists fall into. So while most cyclists know enough to increase their intake of fluids in hot and or humid conditions, most don’t adjust according to how far they plan on cycling.

“Providing a set fluid prescription and volume as a blanket guideline and replacement strategy clearly does not offer a benefit to cycling performance for all individuals over a range of exercise durations, intensities and environmental conditions,” the researchers said.

There may be some circumstances — such as cold weather conditions when your thirst mechanism falls behind your body’s actual need to replace fluids — when a more planned drinking strategy is necessary. In those cases, the researchers concluded that cyclists should aim for 0.15-0.20 mL of fluid per minute per kilogram of body weight for rides between one and two hours, and 0.14–0.27 mL of fluid per minute per kilogram of body weight for rides more than two hours.

The bottom line is there are performance consequences for cyclists who drink too much and drink too little. So avoid emptying your water bottle during short, intense rides, even on hot days. But let thirst be your guide for most distances that keep you on your bike for more than an hour. This simplified plan not only requires less preparation before getting on your bike, you’ll pay less attention to the mechanics of staying well hydrated while in the saddle. So go ahead and give yourself permission to be more in the moment when on your bike and forget about worrying about the right time to grab your water bottle.


Source: National Post