Beating the Heat: Using Bicarb Supplementation and CORE Sensors to Support Performance in Hot Conditions

Performing well in hot conditions is one of the biggest challenges endurance athletes face. To better understand how athletes can prepare for and manage heat stress, FLYCARB partnered with CORE to explore whether sodium bicarbonate supplementation can improve performance in the heat, and how it may work alongside heat training strategies.

FLYCARB co-founders Jack Gray and Josh Elston-Carr are both experienced sub-elite runners and strong believers in the “train hot, race cool” approach. Josh put this philosophy into practice earlier this year, finishing 46th at the London Marathon during unseasonably warm conditions. Using CORE’s core temperature monitoring technology, they set out to examine whether combining structured heat training with bicarb supplementation could offer additional performance benefits in warm environments.

Why Heat Training Works

Heat training is a well-established method for improving an athlete’s ability to cope with high temperatures. Regular exposure to heat can increase blood plasma volume, improve thermoregulation, and reduce cardiovascular strain during endurance exercise. Unlike altitude training, heat adaptations can be achieved relatively quickly and are accessible to most athletes.

The challenge, however, lies in executing heat training effectively. Without objective data, it can be difficult to judge whether a session is providing enough heat stimulus or pushing too far. CORE sensors help remove this uncertainty by providing real-time core body temperature data directly to a GPS watch. This allows athletes to adjust clothing, intensity, and session duration based on accurate physiological feedback rather than guesswork.

The Role of Bicarb Supplementation

Sodium bicarbonate has been widely researched for its ability to support endurance performance, particularly during high-intensity or prolonged efforts. More recently, studies have highlighted its potential benefits when exercising in hot conditions.

Research suggests that sodium bicarbonate may help reduce heat-induced hyperventilation, supporting more efficient breathing and oxygen delivery. It has also been shown to help maintain cerebral blood flow, which can protect concentration and decision-making as fatigue increases. In addition, athletes often report a lower perceived effort during exercise in the heat, making hard sessions feel more manageable.

One study concluded that sodium bicarbonate ingestion can reduce hyperventilation and help prevent reductions in cerebral blood flow during prolonged exercise in hot environments. It also reported lower ratings of perceived exertion, offering insight into how bicarb may help limit central fatigue during exercise in the heat.

In practical terms, this means bicarb supplementation may help athletes stay in control, manage fatigue more effectively, and maintain performance when temperatures rise.

These benefits have also been seen in competition. At the World Championships 100km in India, three British team athletes used FLYCARB’s BICARRB supplement to cope with extreme heat and demanding conditions, contributing to a team bronze medal finish.

Testing CORE and BICARRB Together

To explore the combined effect of heat training and bicarb supplementation, a small internal trial was conducted using controlled indoor sessions. Environmental conditions, clothing, and power output were kept consistent. Core temperature was monitored using CORE sensors, alongside heart rate and perceived exertion.

(Results to be added after second trial)

While the findings were preliminary and anecdotal, the outcomes reflected what existing research suggests. Sessions completed with BICARRB felt easier, core temperature responses appeared more stable, and overall effort felt more manageable compared to sessions without supplementation.

Although further testing is needed, this early work highlights the potential synergy between heat training and bicarb supplementation. Together, they may offer athletes a practical and effective way to improve performance and resilience when racing or training in hot conditions.