Can being in the heat cause MS flare-ups? Yes, heat sensitivity is very common with MS — between 60% and 80% of people with MS experience a temporary worsening of symptoms when exposed to heat or when their body temperature rises. Even a tiny change in core body temperature (as little as a quarter of a degree) can trigger Show Full Answer
Can being in the heat cause MS flare-ups? Yes, heat sensitivity is very common with MS — between 60% and 80% of people with MS experience a temporary worsening of symptoms when exposed to heat or when their body temperature rises. Even a tiny change in core body temperature (as little as a quarter of a degree) can trigger this.
This happens because MS damages the protective coating around nerves (myelin). When your body heats up, it becomes even harder for those already-vulnerable nerves to send signals properly — sometimes slowing down or even blocking them entirely. The symptoms most commonly triggered by heat include:
- Fatigue and brain fog
- Blurred vision (known as Uhthoff's phenomenon)
- Muscle weakness or spasticity
- Balance and coordination issues
- Difficulty concentrating
As one MyMSTeam member put it, hot days feel "like trying to walk through Jell-O and everything hurts." The good news is that these heat-triggered symptoms are usually temporary and tend to ease once your body cools back down. However, it's worth being cautious — heat-related fatigue combined with muscle weakness can increase the risk of falls.
Staying cool with light, breathable clothing, avoiding hot environments during peak heat, and keeping air conditioning handy can all help manage this. If heat sensitivity is significantly affecting your daily life, it's worth discussing with your neurologist.
July 22