A sauna-style training suit built from heat-retaining fabric, used in boxing, MMA, and combat-sport training rooms for decades. The suit traps body heat during a session, which raises perspiration significantly compared to normal training gear.
The practical case for it is heat acclimatization and warm-up — getting muscles warm faster in a cold gym, or training in conditions that simulate a hotter environment. The full-coverage cut with elasticated cuffs and ankles keeps the heat in through movement.
Being straight about the weight question: any drop on the scale after wearing one is water lost through sweat, and it comes back as soon as you rehydrate. It isn't fat loss. Fighters who cut weight this way are making a temporary, deliberately reversed change before a weigh-in — not losing body fat.
Because it raises core temperature and fluid loss, keep sessions sensible, drink water throughout, and stop if you feel dizzy or unwell. If you have any heart, blood pressure, or heat-sensitivity condition, check with a doctor before using one.
