Published: 16:00 BST, 23 August 2026 | Updated: 16:12 BST, 23 August 2026
You do everything right. You hit the gym five or six days a week, you eat clean, and you never skip leg day.
So why do you still feel bloated, exhausted and like you're catching every cold going around?
According to fitness and health experts, the answer might be surprising – every time you push yourself through another punishing workout without giving your body the recovery it needs, you are messing with the delicate balance of your gut.
'Productive training stress follows a simple pattern: you challenge the body, you recover, and you come back stronger,' said Dr Desi Bartlett, creator of The Body Mind Work Out and a certified personal trainer.
'The line gets crossed when the stress keeps coming and the recovery never catches up.'
That imbalance, Bartlett told Daily Mail, doesn't just leave you tired. It can throw your gut and with it, your immune system, your mood and even your long-term health into chaos.
Long, high-intensity endurance sessions – particularly running – tend to be the biggest gut stressors, largely because of reduced blood flow to the digestive system combined with repetitive impact, Bartlett says.
Working out and pushing yourself too hard without allowing time for proper rest and recovery could be silently damaging your gut
Daily HIIT sessions without rest days are a close second, as they can keep the body in a state of repeated physiological stress, contributing to elevated cortisol levels.
Cortisol is a hormone produced by the adrenal glands and is essential for metabolism, and the sleep-wake cycle.
Cortisol, commonly known as the 'stress hormone' itself isn't bad – the concern is prolonged or poorly regulated elevated levels, which can occur with the combination of intense training without sufficient recovery, Bartlett explained.
Heavy lifting is generally easier on the gut, Bartlett said, but training at high intensity six or seven days a week without a planned period of reduced training intensity or volume can create the same recovery deficit.
'The pattern matters more than the modality,' Bartlett said. 'Intensity plus duration plus no rest is the problem formula.'
During an intense workout, blood is diverted away from the digestive system and sent to the muscles, heart and lungs that need it most, a short-term survival response, she added.
