Will a Holiday Ruin My Fitness Progress?

You've put in the hard work at the gym for months, maybe even years - so it's natural to wonder if a week or two on holiday will undo it all. Will your muscles start shrinking the second you hit the sun lounger? Is skipping your usual workouts really as risky as it feels?

The good news is: it's not that dramatic. Let's look at what actually happens to your body when you take a break, what the science says about fitness and holidays, and some simple ways to keep your progress (and peace of min) intact while you enjoy your time off.

Why a Holiday Might Be Exactly What You Need?

Let's face it: most of us are busier and more stressed than ever, constantly jugging work, training, screens, and daily demands. It's no surprise that 84% of UK adults say they've felt overwhelmed by stress in the past year (Mental Health Foundation, 2018). In a world that never seems to slow down, actually stepping away on holiday can be one of the most powerful things you do for your health.

Holidays give you permission to switch off, recharge, and enjoy a kind of rest that's hard to find in everyday life. And we're not just talking about sleep - rest can mean everything from quiet moments in nature, to laughter with friends, to finally escaping from your notifications for a few days. Research highlights that there are actually seven kinds of rest - physical, mental, emotional, social, sensory, creative, and spiritual (Dalton-Smith; APA) - and a good holiday often helps you experience several at once.

Science backs up just how powerful this can be: taking time out improves mood, strengthens your immune system, helps regulate stress hormones, and lifts your motivation and wellbeing (Goto et al. 2018; Albulescu et al.2022). Even short breaks, or "micro-rests", can reduce fatigue and help your brain and body recover, and after a proper holiday, people often report not just better sleep and energy, but a fresh sense of excitement to get back into their routines (Hübner et al 2022; The Wellbeing Thesis, 2023). In other words, when you feel burned out or stuck in a rut, a holiday isn't just a holiday - it's a real, research-backed way to reset and come back stronger.

So...What About My Fitness Progress?

Muscle Mass and Strength: Harder to Lose Than You Think

One of the most common worries before a holiday is losing muscle or strength from time off the gym. The science, however, is very reassuring. Studies consistently show that taking one to three weeks off - whether it's complete rest or ust reduced training - has little to no meaningful impact on muscle size or strength (Callahan et al, 2021; Gavanda et al 2020, Encarnaçāo et al, 2022). If you notice your muscles feel or look a bit softer after a break, it's almost always due to a drop in muscle glycogen and water, not real muscle loss. These changes are reversed quickly once you get back to your regular routine (Encarnaçāo et al, 2022).

Plus, the phenomenon of "muscle memory" means you'll regain any lost size or strength much faster than you did when you first started training. Ever if there is a minor decline, it's usually temporary and your progress rebounds rapidly.

Cardiovascular Fitness: Quicker to Drop, Quicker to Return

Your cardiovascular fitness (endurance, VO2max), does tend to decline a little faster than muscle, but it's not as fragile as you might think - and it's quick to bounce back. Research indicates that after one to two weeks with no structured aerobic exercise, there can be a noticable drop in cardiovascular performance (Callahan et al, 2021; Chen et al, 2022). This is mostly due to reduced plasma volume and changes in how efficiently your cells produce energy.

But, importantly, most holidays aren't completely sedentary. Exploring a city, swimming, hiking, or simply walking more than usual all contribute to maintaining your cardiovascular base. Even low-to-moderate activity helps you keep most of your fitness, and any decline you do experience is minor and quickly regained once you're home.

Weight Gain: How Much Is it ?

Holiday weight gain is a common concern - and it's true that studies show the average person may see an increase of up to 0.5kg (about one pound) after a week away, which could add up to around a kilogram if you're gone for two weeks (Cooper & Tokar, 2016). That sounds like a lot, but here's the important context: most of the gain isn't actual body fat. Increases on the scale during holidays are usually due to extra water retention and glycogen from eating more carbs, as well as saltier foods, rather than true fat gain. Once you get back to your normal habits, these numbers typically drop within a week or two.

Still, if you want to keep any gain to a mininum, staying active is key. Most holidays involve more wakling than your usual daily routine, whether you're exploring a city, heading out on day trips, or just being on your feet more. This extra movement helps balance out indulgent meals and makes it much harder to gain real fat.

It also helps that holidays often mean plenty of access to fresh, local fruits and veggies, which are naturally filling and lower in calories. Even if you're eating more often, filing up on these foods supports your body in staying balanced.

So, yes, the scale might go up temporarily, especially over two weeks - but with a bit of daily activity and smart food choices, any gain is usually minor, mostly water, and quick to disappear once you're home and back in your routine. The main thing; stay active, enjoy real food, and don't let short-term changes stress you out.

Jet Lag and Performance: Short-Lived Setbacks

If your holiday involves changing time zones, you might experience jet lag, which can temporarily disrupt sleep and lower body strength and endurance. Research shows that performance can dip for three to four days after traveling east across multiple time zones (Botonis et al,2025; Fowler et al, 2015). Poor sleep during and after travel can also increase cravings for calorie-dense foods and make it harder to feel motivated to move (Ahmed et al, 2024). The good news is these effects are short-lived. Most people find their performance and appetite normalise within a few days of getting back into a regular routine. Prioritising sunlight, hydration, and gentle movement speeds up the process and helps your body reset.

Summary

If you’ve ever worried that a holiday will erase all your fitness progress, you’re not alone—I’ve been there, too. But the science (and real-life experience) says otherwise: a week or two off won’t undo your hard work, and most of any weight gain is just water, not fat. In fact, a break away from routines, stress, and screens is one of the best things you can do for your body and mind. So go enjoy your holiday, keep moving in ways that feel good, try the local food, and trust that your fitness will still be there when you get home—often with even more motivation to keep going.