As the UK endures a record-breaking heatwave, with temperatures expected to reach 39°C on Thursday and possibly 40°C, personal trainer Sam Hayward, who lost 17 stone, has explained why people may see a temporary increase on the scale.
Body's Response to Heat
In a TikTok video, Hayward reassured viewers that weight gain during hot weather is normal and not fat. He explained that when dehydrated, the body thinks it is in a drought and releases hormones to hold onto water.
“When you’re dehydrated and that hot, your body thinks we’re in a drought. So it ramps up a load of hormones, causing us to hold as much water as possible to keep us cool,” Hayward said.
Hormonal Mechanism
The body releases aldosterone, a hormone that signals the kidneys to retain extra water and sodium, increasing fluid volume. This leads to a temporary weight gain that subsides once the body adapts or temperatures cool.
Additionally, blood vessels near the skin widen to release heat, allowing fluid to leak into surrounding tissues and causing swelling in hands, ankles, and stomach.
Dietary Factors
Warmer weather often leads to higher intake of salty snacks and sugary or alcoholic beverages, which worsen fluid retention and make people look more swollen.
“So don’t be surprised if over the next couple of days, you gain a handful of pounds. It’s nothing. It’s just water. Once the weather resumes back to normal, you’ll be fine,” Hayward concluded.
