How to use CORE Body Temperature Monitoring

Access to accurate core body temperature monitoring for sports people has been traditionally very limited. Ingested electronic-pills or rectal thermometers are accurate but rely on the invasive hardware and additional expertise to administer and capture the data. This has also meant there are very few studies and resources for using core body temperature for sports compared with other sports performance topics such as heart rate variability and power output.

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As a vital metric, the core body temperature is an important field knowledge and the availability of the easy-to-use CORE Body Temperature Monitoring technology can deliver sports people with invaluable data to help them train and perform at their best.

When the core body temperature rises above a threshold, the performance (power) decreases. As the body heats and diverts more energy to pumping blood to the skin to cool the body, there is less blood powering the muscles and power output drops.

On this page we outline some of the main areas of attention in which athletes can benefit from accurate core body temperature monitoring.

Heat Stress

During sporting events in hot weather conditions as well as for athletes who are unprepared or over-exert, there is an increased risk of heat stress.

The risks can be varied, a minor Impact can mean energy is lost (bonking / blowing up) with under-performance and possible withdrawal from competition.

In higher risk instances this can be life-threatening and result in collapse with medical attention required. Recovery following a severe heat stress can take weeks or months.

Core body temperature insights from training help each individual to better understand their own limits and they can use the following training approaches to improve their physical condition to avoid heat-stress.

Heat Acclimation / Heat Adaption

Heat Adaption or Acclimation is training to condition the body to improve performance in hot weather environments competition. Athletes can do heat training in hotter environments, in a climate chamber or using other approaches (such as wearing winter clothing) to elevate their core body temperature during training and trigger the physiological conditions.

A detailed overview of this is available in The Science of Heat Training and the accompanying scientific studies and literature.

Heat Training

Heat Training is similar to Heat Acclimation / Adaption though the goal is conditioning the body (through exposure to heat) to increase the available power output for mild and cooler racing conditions.

It is similar to the approach used in Altitude Training by conditioning the body to become more effective. Scientific studies show that athletes have a higher response rate to Heat Training compared to Altitude Training.

Some scientific research also shows conflicting results with regard to the effectiveness of heat training for competition in mild and cooler weather while the benefits of heat acclimation /adaption is broadly accepted among sports scientists.

Further details are available for Heat Training and Heat Block Training

Heat Ramp Test

As part of Heat Acclimation and Heat Training, the Heat Ramp Test is a repeatable test that is performed indoors and helps an athlete identify the best 'heat training zone' for them. It is also used to quantify the results (before and after) in which successful heat training would show an increase in power output and duration.

This test can be modified to suit training conditions and this is described in more detail in the Heat Ramp Test.

Pacing & Strategy

Understanding your own performance and relationship with core body temperature, such as your own thresholds and effective cooling approaches, can help prepare for competition.

For solo-events such as Triathlon, the pacing strategy can account for the gradual increases in core body temperature with the goal of stabilising it with active cooling.

In team-events such as day-races or stage-races in cycling, cooling ahead of ascents, pacing during lead-outs (to avoid bonking), hydration and managing recovery can all form part of individual rider and team strategy.

Active Cooling

The result of elevated core body temperature is that the natural thermoregulation diverts more blood to the skin to help cool, this in turn reduces the amount of blood available to the muscles for power generation. By keeping the core body temperature lower, more power is available.

Thermoregulation can vary from person to person along with the individual response to cooling. In training, sports people should seek to identify the approaches that are the most effective. These are some of the common approaches.

Reducing power output is effective although in competitive sports, this may not always be an option. Physical intensity has the single biggest impact on the core body temperature in active sports.

Wind Cooling and wicking has a significant impact on cooling. A triathlon competitor on the cycle-leg with a higher speed (and more wind) will be able to remain cooler compared to the run-leg if they maintain the same power output but have a lower moving speed and thus a lower cooling effect from the wind.

Water Cooling by tipping a bottle of water over the head and body and even sprays or showers that may be available for some sports people can help slow the increase or core body temperature.

Sports Wear is relevant with regard to the material selection (cooling / wicking) as well as planning-ahead and 'shedding' warm layers of clothing in advance. Sports wear with integrated ice-packs for example can be used ahead of the race by athletes competing in short-distance races.

Hydration can also impact cooling and be timed (frequency or at key points in a race) as well as the temperature of the fluids.

Active cooling is also related to the strategy and pacing plan. Being familiar with the individual response and 'planning ahead' (for example depending on the course and conditions) is part of the active cooling approach.

24/7 Monitoring

While 36.9ºC (98.4ºF) is considered to the average human body temperature, not only does this vary between people, the temperature also fluctuates during the day - this fluctuation is the Circadian Rhythm.

For women, menstruation, pregnancy and menopause all impact the core body temperature.

As a holistic approach to athletic training, the core body temperature can reveal insights into the well-being of athletes as well as be used to define and adjust the time periods in which an athlete is able to perform best. For example, jet lag can be seen in the Circadian Rhythm.