How to coach your body for decent weather when you are energetic or work outdoors

Global warming is making outdoor activities difficult — especially exercise. Indeed, now we have a really small buffer to tolerate a rise in body heat. An increase in core temperature of only three degrees Celcius might be life-threatening, even for young healthy adults.

There are several ways to assist prevent a deadly rise in core temperature while being physically energetic in the warmth. There are quite a few pre-cooling strategies that can assist. Most practical of those is consuming a chilly drink (or higher yet, an ice slurry or slushie) prior to exercise. But “training” your body to manage higher in the warmth is one of the best defence.

The strategy of warmth training is especially necessary for endurance athletes. Athletes who incorporate even a modest heat acclimating protocol before competing in the warmth on average perform higher and are less prone to require medical attention for heat-related injuries.

However, given our warming environment, it could be time to contemplate heat training even for non-athletes, especially for people working outdoors.

While heat acclimation training is most frequently utilized by endurance athletes, it was first developed for underground gold mine staff within the Fortieswho were exposed to environmental temperatures exceeding 50 C with humidity near 100 per cent.

How does heat acclimation help?

The advantages of warmth acclimation are a growing area of research. In fact, the advantages seem to increase beyond being more heat tolerant, and into improvements for general cardiovascular health — generally known as heat therapy.

For improvements in heat tolerance, nevertheless, the first advantages are quite easy:

1. It lowers our resting body temperature, which provides a bigger reserve for our core temperature to rise before problems occur.

2. It increases our sweating rate, which optimizes our evaporative heat loss potential, thereby attenuating the rise in core temperature.

3. It increases our plasma volume (the liquid a part of blood), which lowers the cardiovascular strain imposed by an increase in core temperature, and provides a bigger reserve to take care of sweat rate (sweat comes from plasma).

In addition to those three aspects is an improved perception of thermal comfort. There are also other more nuanced advantages for improved heat tolerance, including salt conservation, metabolic and anti inflammatory effectshowever the three listed above are most vital.

Methods of warmth acclimation

Heat acclimatization and warmth acclimation are barely different: It is named heat acclimatization when it occurs naturally over an extended period, and warmth acclimation when done “artificially” or purposefully over a shorter duration. Both forms confer advantages for warmth tolerance, but they usually are not entirely synonymous.

Heat acclimatization can, and does to some extent, occur naturally in people who find themselves consistently exposed to hot and humid environments. But for those of us living in a humid continental climate (which incorporates most populated regions above the fortieth parallel), or for many who normally seek air-conditioning in the summertime, natural heat acclimatization rarely occurs. It takes a little bit of work.

The degree of warmth adaptation will depend on the duration, intensity and frequency of warmth exposure.

The gold standard for warmth acclimation involves maintaining an elevated core temperature by one to 2 degrees Celcius for no less than 60 minutes, for at least five consecutive days, or over a two-week period allowing for a number of rest days. But importantly, the most important adjustments occur throughout the first few days, and start to have a ceiling effect around two weeks, with minor advantages thereafter.

The advantages of warmth acclimation for improved heat tolerance unfortunately don’t last without end. They are largely retained for about one week following the last heat exposure, but roughly 75 per cent of the advantages will likely be lost after three weeks with none heat exposure. Thankfully re-acclimatization is mostly easier, and a “regular state” heat acclimated status might be achieved by maintaining some form of warmth exposure no less than 3 times per week.

At-home heat acclimation

For those without access to a heat chamber or thermistor (for instance an ingestible internal thermometer) to observe your body’s core temperature, heat acclimation continues to be possible. All you would like is a bath.

A recent study suggests that an efficient (and practical) protocol for partial but meaningful heat acclimation is just three consecutive days of soaking in 40 C water for about 40 minutes, immediately after about 40 minutes of moderate-intensity exercise at room temperature.

The secret is that the exercise should be strenuous enough to bring your body temperature past a threshold for sweating, and that you simply immediately enter the bathtub after the exercise. According to the study’s authors: “Taking a hot bath submerged to the neck, for as much as 40 minutes, following habitual training in temperate conditions, presents a practical and economical heat acclimation intervention — eliminating the requirement for an increased training load, access to an environmental chamber or relocation to a hot climate.”

Ultimately, strategies to avoid excessive heat exposure are still paramount, especially for many who are more vulnerable to heat-related injuries, including older adults and other people with conditions similar to heart disease and diabetes.

But it’s becoming increasingly apparent that heat exposure is inevitable for many who work or are energetic outdoors. Incorporating a heat acclimation protocol, together with the more recognized heat-mitigating strategies — including sun protection and maintaining hydration — provides your body with one of the best defence against heat-related injuries.