Keep cool with the latest innovation in aerodynamic water bottle design

As summer temperatures trend towards increasingly hotter racing, staying cool can make or break your race. Canadian company, Endurance Innovation, has designed a water bottle that brings your forearms in contact with ice while riding. Contact with a cooling agent can help keep core temperature down, decrease perceived exertion and improve your performance.

The Cool Bottle fits between your aero bars by attaching to your arm rests underneath the pad. To leverage the advantage of thermodynamics, the bottle is filled with water and frozen before use. When attached to the bike, your forearms lay against the frozen bottle, cooling a significant surface area of your skin. The melting ice can help prolong the time until your core body temperature rises, reducing the overall level to which your temperature elevates over the course of the bike leg.

Energy transfer decreases core temperature

The team at Endurance Innovation employed cutting edge science and the principles of thermodynamics to arrive at a practical design that is easy to install and easy to use. The frozen water stores energy, which is then released to help cool down the body more than drinking ice water, the company’s science-based analysis claims. In addition to the energy transfer, the water at your disposal, conveniently situated between your aero bars, is ice cold, doubling down on its cooling effects.

When the body no longer needs to send its blood supply to the skin for cooling, it can continue to deliver the oxygen-carrying blood to the working muscles. Not only does this affect perceived exertion, but improves muscle performance. As described on the product website, the designers explain how this energy transfer works.

“The natural circulatory system cycles heat from the core of our bodies to the surface, leveraging highly vascularized areas with our natural blood flow to transfer excess metabolic heat to the environment.

“When it’s hot or humid, our body can’t do this fast enough, and we start to sweat. When the sweat doesn’t evaporate fast enough and our bodies keep building up heat, we either slow down (bad) or overheat (very bad!).”

The company claims the energy within the ice is about five times more cooling than ice water, and works to extract excess heat from your body. Keeping your blood cooled as it courses through your body and returns to your core allows it to absorb more heat in a cyclical pattern.

Putting it to the test

An athlete-focused 45 minute time trial test in the heat revealed that, on average, a rider’s heart rate was reduced by up to seven beats per minute and a reduction in body core temperature of half a degree Celsius.

To test the veracity of these claims myself, I attached a Cool Bottle to my triathlon bike, full of frozen water, and slipped the neoprene sleeve that comes with it over the ice block to reduce the rate of melting.

The bottle itself was easy to install, in particular because there is a series of short videos with step-by-step instructions on the company’s website. At five feet three inches, I ride the smallest Cervelo triathlon bike frame. May aero bars are installed quite close together, but given the wide range of holes with which you can choose to install the water bottle holder beneath your arm rest pads, I had no problem fitting it on.

The bottle position is also adjustable in height and distance from the rider, so I found I could maneuver the bottle in such a way that my reach was comfortable when positioning my arms and when drinking.

There is some trial and error involved in filling the bottle with the correct amount of water before freezing to ensure it is not overfilled. The neoprene cover that slips over the bottle did prolong the time to melting, as I tested the frozen bottle without the cover on the same day in similar temperatures and found without the cover the ice melted faster.

Dialling in position and effectiveness

The coolness from the frozen water was applied correctly, from a positional point, on my forearms. Given my location, the temperatures have yet to reach peak heat, so I was unable to put the system to a more robust test in harsher conditions. I did not test on race day, as the opportunity was not there. However, I can see a benefit on certain courses known for their extreme heat.

My one concern is keeping the bottle frozen in transition until it is time to ride. A mini cooler could do the trick, brought into T1 on race morning. If the course had a reputation for starting cool and not warming up until that afternoon, this issue would be mitigated given the early start time for most races and the average time for the longest of races being in the range of one to one and a half hours. It is possible that the ice would not melt significantly in that time and that a cooling benefit would be achieved even if it wasn’t the maximum amount.

Using the bottle in training alone could help an athlete train harder, thereby producing a better result on race day even without the bottle. Ideally, the bottle would be used with other cooling system strategies to extend the amount of time one worked at keeping body core temperature low.

The Cool Bottle could be an integral tool used as part of a larger cooling strategy, in which an athlete could also use ice on the bike and run course and follow their hydration plan accordingly.