Training with extra clothing is not training in the heat

Every summer the same scene repeats itself: athletes training in several layers of clothing, convinced that this will help them acclimate to the heat. But does it actually work?

Every summer the same idea comes back. Runners in sweatshirts. Cyclists fully covered up. Athletes chasing more sweat to "get used to the heat."

The logic seems simple. Sweat more, adapt more.

Physiology doesn't work that way.

NoteThe body doesn't respond to sweat. It responds to the thermal stress it actually receives. And the two don't always match.

Understanding that difference is fundamental to designing effective acclimation protocols.

For years, sweat has been associated with better heat adaptation. It's an easy idea to grasp, but physiologically incomplete. More sweat. More heat. More adaptation.

But sweat is only a thermoregulation mechanism. It's not the goal of training. It's a consequence of the body trying to dissipate heat.

On its own, it doesn't tell us whether the physiological adaptations are actually happening.

Heat acclimation involves complex changes. Among them:

• Increased plasma volume.
• Better ability to dissipate heat.
• Lower heart rate for the same intensity.
• Progressive drop in core temperature.
• Changes in sweat response.

None of these adaptations depends only on sweating more; they depend on the physiological response to the thermal stimulus.

These adaptations appear when the body receives a sufficient, repeated thermal stimulus. Not just because clothing makes us sweat more.

The key is not to produce more sweat. The key is to design and control the thermal stimulus.

For adaptation to happen, variables like these must be controlled:

• Duration of exposure.
• Exercise intensity.
• Core temperature reached.
• Session frequency.
• Recovery between stimuli.

Without that control, it's very hard to know whether the athlete is really adapting or simply putting up with more discomfort.

Training overly wrapped up can raise perceived effort. It can also elevate heart rate and make recovery harder.

But that doesn't guarantee a better adaptation. In some cases it can add fatigue without providing any additional adaptation.

The answer isn't a plain yes or no. It depends on context.

In certain situations, extra clothing can be used as a tool to modify thermal stress. But it should never be the goal.

The goal always has to be to trigger the physiological adaptations that improve performance. And that means interpreting the body's response, not just amplifying the sensation of heat.

The question shouldn't be "how can I sweat more?" but "how can I trigger a better physiological adaptation?"

• Sweating more doesn't imply adapting better.
• Acclimation depends on the physiological stimulus, not the amount of clothing.
• Core temperature matters more than the subjective sensation of heat.
• A protocol without control can produce more fatigue than adaptation.
• The goal is to interpret the body's response.