Fueling for Long Runs and Rides with Autoimmune Disease: Avoid Fatigue, Gut Issues, and Flares
Training for a long trail run, a big mountain objective, or an all-day ride asks a lot of your body.…
You log consistent miles on the trails. You’ve summited some serious peaks. You’re in good shape, so your heart health and blood sugar must be in good shape too, right? Not necessarily.
Many athletes are surprised to discover that they have heart health issues or blood sugar imbalances. They may find out through lab work at a routine physical, or more frighteningly, when they have a cardiac event. Let’s take a look at “John,” a case study “client” based on several actual clients I’ve worked with, to see what heart health and blood sugar issues can look like in an outdoor athlete.
John jolts awake at 6:00 am on Saturday—his usual wake time on the weekend so he can get out for a long ride. He’s an endurance cyclist who pushes hard, logging serious vertical and mileage every week. The heart attack he had last year during a high-altitude race, the stent now in his coronary artery, and the statin his doctor prescribed for high cholesterol and triglycerides haven’t slowed his training. After pulling on his kit, he heads to the kitchen for pancakes with butter and syrup, orange juice, and coffee. Thirty minutes later, he’s on the bike with a bottle of sports drink and a handful of gels.
Over four hours, he consumes four gels and 24 ounces of sports drink. His teeth feel sticky from the sugar, his energy fluctuates, and his stomach protests—but he knows he needs carbs to fuel his training. On the way home, he stops for grocery store sushi and chugs Powerade. Once home, he makes a ham and cheese sandwich, props his feet up, and settles in to watch football.
John’s story is more common than you’d think! As outdoor athletes—whether you’re a trail runner, alpinist, backcountry skier, or multi-day backpacker—we often assume our high activity levels grant us immunity from metabolic and cardiovascular problems. We’re out there logging miles in the mountains, and pushing our bodies to incredible limits. This can make us feel bulletproof.
However, the surprising truth is that being an athlete doesn’t automatically guarantee a healthy cardiovascular system or optimal blood sugar control. And here’s the good news—optimizing what’s called your “cardiometabolic health” won’t just help you live healthier for longer. It’ll make you a better athlete right now. In this blog, you’ll learn why cardiometabolic health matters for athletes and how to optimize yours.
Cardiometabolic health refers to the combined health of your cardiovascular system (heart and blood vessels) and your metabolic system (how your body processes and regulates blood sugar). These two systems are deeply interconnected—so much so that problems in one almost always affect the other.
Think of it this way: Your heart is the pump that delivers oxygen, glucose, nutrients, and hormones to your working muscles during that alpine start or that long trail run. Your blood vessels are the highways that transport everything your body needs (blood carrying oxygen and nutrients). And blood sugar? That’s the fuel that powers nearly every function in your body, from muscle contractions on a steep climb to the mental focus you need to navigate technical terrain.
When your cardiometabolic health is optimized, you have:
When they’re not? You might experience energy crashes mid-run, poor recovery, increased injury risk, and—over the long term—serious health consequences that could sideline you permanently.
Many healthcare professionals assume their active patients are immune to cardiometabolic problems. After all, you’re logging serious training volume, right? Unfortunately, research tells a different story.
Both scientific research and stories in the media indicate that athletes are not immune to cardiometabolic health issues. (Source, Source)
Endurance athletes – who pride themselves on their cardiovascular fitness – can actually experience increased risk of coronary artery disease (CAD) and coronary artery calcification, a condition associated with heart attack risk. One study found that even masters endurance athletes with low atherosclerotic risk profiles showed evidence of subclinical coronary artery disease.
Athletes in sports that value higher body mass may face an increased risk of metabolic syndrome. And masters athletes (those over 40) are at particular risk for age-related cardiometabolic concerns that standard annual screenings might miss.
The bottom line is that while exercise is incredibly powerful (and crucial) for promoting cardiometabolic health, it isn’t enough on its own to optimize this critical aspect of your health—especially if your nutrition is less than ideal.
As outdoor athletes, we’re obsessed with metrics. Heart rate zones. VO2 max. Grams of carbs per hour. Vertical gain per week. But here’s what most of us aren’t tracking: the actual health of our cardiovascular system and how well our bodies balance blood sugar throughout the day.
You might monitor your heart rate during intervals or tempo runs, but are you thinking about your heart from a health perspective? You probably pay attention to blood sugar in terms of fueling during a long effort, but what about blood sugar balance during the other 23 hours of your day?
Your cardiometabolic health is foundational to your entire body’s health, your athletic longevity, and your performance.
It affects:
Blood sugar isn’t just about avoiding bonking on a long run. It’s the energy that fuels nearly every function in your body. Your cells—and the mitochondria (your little energy powerhouses) inside them—use glucose to make ATP, the cellular fuel that drives everything from muscle movement to nerve transmission.
Well-regulated blood sugar means:
Poor blood sugar control, on the other hand, creates energy fluctuations that make it difficult to sustain optimal performance. It also increases inflammation, impairs recovery, and over time, may lead to insulin resistance, prediabetes, and type 2 diabetes.
Just as you might test your VO2 max or lactate threshold, it’s crucial to assess your baseline cardiometabolic health. Here are the key markers to get tested at least once a year:
Cardiovascular Health Markers:
Blood Sugar Control Markers:
Bonus tool: Continuous glucose monitors (CGMs) are becoming more popular among athletes. While they require a prescription, they can help you understand how specific foods, training practices, and lifestyle habits affect your blood sugar in real-time. Some athletes and researchers suggest CGM monitoring may help improve endurance performance by optimizing fueling strategies.
Here’s where the rubber meets the trail. Your nutrition choices have profound effects on your cardiometabolic health—and your performance. Let’s break down the key strategies.
Carbs are crucial for outdoor athletes. But not all carbs are created equal. To protect your cardiometabolic health, you need to think about carbohydrate quality.
Carbohydrate quality refers to:
Research consistently links processed and refined carbohydrates—white bread, white pasta, pastries, simple sugars—to blood sugar and heart health problems. Instead, choose whole-food carbs for the majority of your intake:
These whole-food carbs contain fiber that helps “meter out” your blood sugar response, ensuring more stable energy. They also provide vitamins, minerals, and phytonutrients that regulate inflammation, support ATP production, and benefit your active body in countless ways.
The bottom line: Choosing whole-food carbs for the majority of your intake is one of the best things you can do for cardiometabolic health.
When you eat carbs matters as much as what carbs you choose. Fast-digesting carbohydrates—bananas, white potatoes, sports drinks, gels—have their place, mainly around training. A gel during a long trail run or a sports drink before a hard climb makes sense. But these shouldn’t be scattered throughout your day.
Fast-digesting carbs consumed before or during training provide quick energy because they rapidly increase blood sugar. The rest of the time, stick with whole-food carbs. Research shows that whole-food carbs can regenerate glycogen as effectively as refined carbs after exercise.
Practical example: Before your Saturday long run, have a banana with nut butter. During the run, use gels or sports drink as needed, or even a more whole-food oriented carb option, like dates. After the run, recover with a meal that provides a balance of protein, carbs, healthy fats, and phytonutrients – try a sweet potato with olive oil, grilled chicken or salmon, and seasoned and salted roasted vegetables.
One of the most effective strategies for balancing blood sugar is pairing carbohydrates with protein. Protein slows gastric emptying and the rate at which glucose enters your bloodstream, creating a gradual rise in blood sugar rather than a spike.
In practice:
This simple strategy dramatically improves blood sugar stability, energy levels, and recovery.
Ultra-processed foods—breakfast cereals, chips, candy, sugary drinks, even some “health” foods like certain protein bars and vegan meat alternatives—are made from extracted substances like starches, oils, added sugars, and emulsifiers. They bear little resemblance to whole foods and are linked to cardiometabolic diseases. (Source)
Swap ultra-processed foods for minimally-processed whole foods: fresh fruits and vegetables, meat, poultry, seafood, eggs, nuts, seeds, whole grains, and quality dairy products. These foods are nutrient-dense and free from added sugars, refined oils, artificial flavors, and preservatives.
“Eat the rainbow” isn’t just Instagram-worthy advice—it’s backed by science. Each color group provides specific phytonutrients linked to cardiometabolic health benefits:
Aim to include multiple colors in every meal. Your post-run recovery plate might include grilled salmon (protein), roasted sweet potato (orange), sautéed kale (green), and blueberries (blue/purple).
Beyond whole foods, certain nutrients deserve special attention:
Omega-3 fatty acids: Found in fatty fish (salmon, sardines, mackerel), walnuts, and flaxseeds. These support cardiovascular health and reduce inflammation. (Source, Source, Source)
Methylation nutrients (folate, B12, B6): These B vitamins help regulate homocysteine, an amino acid that, when elevated, is linked to cardiovascular disease, endothelial dysfunction, inflammation, increased blood clot risk, and atherosclerosis. (Source) Choose the most bioavailable forms: methylfolate (not folic acid), methylcobalamin (B12), and pyridoxal-5-phosphate (B6).
Let’s address the elephant in the room: the belief that if you train hard enough, you can eat whatever you want. This myth has convinced countless outdoor athletes that high training volume grants immunity from poor nutritional choices.
The reality is that the metabolic stress of hard training combined with the metabolic chaos of poor cardiometabolic health creates a perfect storm of inflammation that can impede performance and recovery.
While there’s absolutely a time and place to enjoy refined carbohydrates as an athlete—during and immediately around hard efforts, or as a special treat—all the training in the world can’t undo the harmful effects of frequently consuming these foods throughout your day.
Here’s your call to action: Schedule an appointment with your healthcare provider to get your cardiometabolic health markers tested. Request the blood tests listed earlier in this article. If your doctor questions why you need these tests as an athlete, share the research showing that athletes are not immune to cardiometabolic problems.
Once you have your results, work with your doctor and a functional nutritionist to interpret them and create a plan for optimization if needed. Functional nutrition support will address all of the crucial nutritional aspects that your doctor is unfamiliar and inexperienced with.
Consider trying a continuous glucose monitor for a month to see how your current nutrition and training practices affect your blood sugar in real-time. The insights can be eye-opening.
Short-term performance gains at the expense of your long-term cardiometabolic health aren’t worth it. You fell in love with the mountains, the trails, the movement, the adventure, the way these activities make you feel alive.
Optimizing your cardiometabolic health isn’t just about preventing a heart attack decades from now—though that’s certainly important. It’s about being able to continue doing what you love for as long as possible. It’s about having the energy and vitality to enjoy not just your training, but your entire life. It’s about being the 70-year-old who’s still hiking peaks, the 80-year-old who’s still skiing (that’s my personal goal)!
Care for your cardiovascular system and balance your blood sugar now, and you’ll be a better athlete for it. You’ll have more stable energy, better recovery, improved performance, and—most importantly—you’ll likely be able to stay active and healthy far longer than those who sacrifice long-term health for short-term performance.
The mountains will still be there in 30, 40, 50 years. Make sure you are too!
The content provided on this nutrition blog is intended for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay seeking it because of something you have read on this blog.
The information and recommendations presented here are based on general nutrition principles and may not be suitable for everyone. Individual dietary needs and health concerns vary, and what works for one person may not be appropriate for another.
I make every effort to provide accurate and up-to-date information, but the field of nutrition is constantly evolving, and new research may impact dietary recommendations. Therefore, I cannot guarantee the accuracy or completeness of the information presented on this blog.
If you have specific dietary or health concerns, please consult a qualified nutritionist or another healthcare professional for personalized guidance.
I empower others through nutrition to conquer their mountain adventures, drawing from my own experiences.
With a background in Biomedical Science and an M.S. in Human Nutrition, I’m a Certified Nutrition Specialist and Licensed Dietitian Nutritionist. My journey in functional medicine has equipped me to work alongside athletes and tackle complex health cases. As a passionate trail runner, backcountry skier, and backpacker, I strive to support others on their paths to peak performance and well-being.
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