Physical stress, like hitting the gym, running, or tackling tough physical tasks, can be a game-changer for your health. It’s like a double-edged sword for your immune system—it can make you stronger or leave you open to getting sick, depending on how you manage it. Let’s dive into how physical stress can boost or weaken your body’s defences, why you might catch a cold on holiday, and how to keep things in balance.

The upside of physical stress
When you exercise—whether it’s a brisk walk, a team sport, or a weights session in the gym, your body gets a wake-up call. It releases stress hormones like adrenaline in small bursts, which act like a cheerleader for your immune system. These hormones send your body’s germ-fighting cells, like little soldiers, racing through your bloodstream to hunt down invaders like viruses or bacteria. A quick workout can make these cells more active and alert, helping you fend off illness. People who exercise regularly often notice they catch fewer colds or bounce back faster from minor bugs. It’s like giving your immune system a turbo boost, making it ready to tackle threats before they take hold. Even a single session of moderate exercise, like a 30-minute jog, can rev up your defences, leaving you feeling stronger and healthier.

When stress becomes too much
But here’s where it gets tricky: too much physical stress without enough rest can turn the tables. If you’re constantly pushing your body—think marathon training, endless gym sessions, or skipping rest days—your immune system can start to crumble. Stress hormones like cortisol stay high for too long, and instead of helping, they start to weaken your body’s ability to fight off germs. This leaves you more likely to catch colds, feel exhausted, or even deal with longer recovery times. For example, marathon runners often get sick right after a big race because their bodies are so worn out from the intense effort. The immune system takes a hit, making it easier for viruses to sneak in.

Why do we get sick right when we go on holiday?
Ever notice how you sometimes come down with a cold just as you start your long-awaited holiday? This is tied to the same idea. Leading up to a holiday, many of us are in overdrive—rushing to finish work, packing, or handling last-minute stress. This constant physical and mental strain keeps cortisol levels high, quietly wearing down your immune system. When you finally relax on vacation, your body lets its guard down, and those germs that were waiting in the wings can pounce. It’s like your immune system takes a breather at the worst time, leaving you sniffling through your beach getaway. Just like marathon runners, your body needs time to recover after intense periods of stress, and that’s when illness can strike.

Keeping the balance
To make physical stress your immune system’s friend, moderation is key. Aim for regular exercise—think 30-60 minutes most days—but don’t overdo it. Mix in rest days to let your body recharge. Pay attention to signs of overtraining, like feeling unusually tired, sore, or irritable. Fuel your body with healthy foods, stay hydrated, and prioritize sleep to keep your immune system strong. If you’re training hard for something big, like a race, or juggling a hectic schedule before a holiday, ease up afterward to give your body a break. Physical stress can be a powerful tool to boost your health, but only if you use it wisely. Treat your body like a teammate—work together, and you’ll both come out stronger!

Nb. Written as Health columnist for the Hibiscus Matters.