Bloating & Exercise: How Runners & Triathletes Can Fix It
We’ve all been there—you're midway through a run, or just finished a tough training session, and suddenly, you feel it: that uncomfortable, swollen sensation in your stomach. Bloating can be frustrating, especially when you're training hard and eating well.
But did you know that bloating isn’t just about what you eat? Hydration, hormone fluctuations, and even how you breathe while running can all play a role. For female endurance athletes, bloating can interfere with performance, recovery, and confidence. So, let’s break down why bloating happens and how to fix it with smarter nutrition, training, and lifestyle tweaks.
Why Do Runners and Triathletes Get Bloated?
Bloating is caused by excess gas or water retention in the digestive system. For endurance athletes, bloating can be triggered by:
1. Eating Too Close to Training
If you eat a large meal too soon before a run or workout, food sits in the stomach while blood is diverted to working muscles. This slows digestion, leading to bloating and discomfort. High-fibre or fatty foods are especially hard to digest pre-run.
2. Dehydration & Electrolyte Imbalance
Not drinking enough water or losing too much sodium through sweat can cause fluid retention, leading to bloating. If you’re training in hot conditions or sweating heavily, proper hydration and electrolyte intake are key.
3. Swallowing Air While Running
Rapid breathing, gulping water, or running at high intensity can cause excess air to be swallowed, leading to bloating and cramping.
4. Hormonal Changes & Menstrual Cycle
Women often experience bloating due to hormonal shifts, especially in the luteal phase (days 15-28 of the cycle) when progesterone rises, leading to fluid retention and digestive sluggishness.
5. Sports Nutrition Products & Artificial Sweeteners
Gels, sports drinks, and protein bars can contain sorbitol, maltitol, or xylitol, which may cause bloating. Some athletes also react poorly to high-fructose drinks or excessive caffeine intake.
6. Gut Imbalances & Food Sensitivities
Undiagnosed IBS, lactose intolerance, or gluten sensitivity can contribute to bloating. If bloating is persistent, it’s worth keeping a food diary and checking for patterns.
How to Beat the Bloat: Nutrition Strategies for Runners & Triathletes
Bloating doesn’t have to derail your training. Here’s how to optimise your nutrition and reduce digestive discomfort:
1. Pre-Run Nutrition: What to Eat & What to Avoid
The goal of pre-run fuelling is to provide energy without causing digestive distress. Stick to simple, quick-digesting carbs.
✅ Best pre-run foods:
A banana with nut butter
Rice cakes with honey
White toast with jam
A small bowl of porridge
A smoothie with oats and protein
🚫 Foods to avoid before training:
High-fibre foods (beans, cruciferous veg)
Dairy (if lactose-sensitive)
Greasy or high-fat foods
Fizzy drinks or sparkling water
2. Hydration & Electrolytes: Get the Balance Right
✅ Pre-run hydration tips:
Drink 500ml of water 30–60 minutes before training.
If training over an hour, include electrolytes (sodium, potassium, magnesium) to replace lost salts.
Avoid gulping water quickly, as this can cause bloating—take small sips instead.
✅ During training:
If running over 90 minutes, sip an electrolyte drink every 15-20 minutes.
Avoid excessive plain water intake (over 750ml per hour), as this can cause hyponatraemia (low sodium levels), leading to bloating and nausea.
3. Post-Workout Recovery: How to Avoid Bloating After Training
✅ Best recovery foods:
Greek yoghurt with berries & honey
A protein smoothie with banana & oats
Scrambled eggs with sourdough toast
Rice with chicken & avocado
🚫 What to avoid post-workout:
Heavy, greasy meals that slow digestion
High-fibre, raw veggies (opt for cooked vegetables instead)
Large portions of protein immediately post-workout (split into smaller meals if needed)
4. Train Your Gut for Race Day
Many endurance athletes struggle with runners' gut due to nerves, nutrition changes, and race-day fuelling mistakes. You can train your gut to tolerate sports nutrition better.
✅ How to train your gut:
Practise fuelling in training with the same gels, drinks, or food you’ll use on race day.
Gradually increase carb intake before long runs so your gut adapts.
Try low-FODMAP sports nutrition if you’re prone to bloating (e.g., Maurten gels, Skratch Labs drink mix).
5. Cycle-Sync Your Nutrition to Reduce Hormonal Bloating
If you notice bloating before your period, tweaking nutrition can help:
Luteal Phase (Days 15-28):
Increase magnesium-rich foods (dark chocolate, nuts, spinach) to reduce water retention.
Eat more complex carbs (sweet potatoes, quinoa) to support progesterone.
Reduce processed sugar & salty foods to minimise bloating.
Menstrual Phase (Days 1-5):
Focus on iron-rich foods (red meat, lentils, leafy greens) to replenish iron stores.
Increase hydration to counteract fluid loss.
Consume anti-inflammatory foods (turmeric, ginger, omega-3s) to ease cramps.
Bonus Tips for Beating Bloating
If you’re still struggling with bloating, these lifestyle changes can make a difference:
✅ Slow down while eating – Chewing food properly reduces swallowed air.
✅ Avoid lying down right after eating – Stay upright for 30-60 mins post-meal to aid digestion.
✅ Walk after meals – A 5-10 min walk after eating can help reduce bloating.
✅ Limit fizzy drinks & chewing gum – Both increase swallowed air, leading to bloating.
✅ Practise belly breathing – Helps activate the diaphragm and support digestion.
Final Thoughts: Take Control of Your Gut Health
Bloating doesn’t have to be an inevitable part of training. By optimising nutrition, hydration, and gut training, you can fuel smarter, feel better, and perform at your best—without worrying about mid-run discomfort.
🚀 Want a personalised endurance nutrition plan to eliminate bloating & maximise performance? Book a consultation with me today.
Stay strong, stay fuelled, and keep running! 💪
Ready to Train Smarter and Feel Stronger?
At Pretty Strong Coaching, we help busy women like you train smarter, fuel better, and achieve your running and triathlon goals - without burnout or overwhelm. If you're ready for personalised coaching that fits into your life, let's chat!
RELATED POSTS
