T1D Exchange sat down with Sam Scott, PhD, CEO and co-founder of Enhance-d, a mobile app and online platform designed to support people living with type 1 diabetes reach their exercise goals. 

Here, we’ll explore Sam’s extensive knowledge as highlighted in his recent book, “Empowered: The Science of Exercise with Type 1 Diabetes,” co-authored with Simon Helleputte, PhD.   

 

Unlocking the answers: T1D and exercise  

Sam, who earned his PhD at Liverpool John Moores University in the UK, explained that a significant part of his learning focused on exercise interventions, including the effects of different types of physical activity and technologies on glucose levels.   

“While conducting these studies, I was really struck by how difficult it is to manage glucose around exercise,” said Sam. “While I don’t live with type 1 diabetes myself, my passion and drive to work in this area have been fueled by experiences I’ve had working with people who do.”  

“Working so closely with the participants who volunteered for my research project, I had the tiniest glimpse into how incredibly challenging exercise was for people with T1D,” he said. “And combined with the fact that so few people were focused on this problem affecting so many, it motivated me to focus on this completely.”  

Upon obtaining his doctoral degree, Sam moved to Toronto to work with renowned researchers Mike Riddell, PhD, and Dessi Zaharieva, PhD, after which he relocated to Switzerland to do a second postdoc examining nutritional and exercise interventions and working with professional athletes.   

“The experience of working with athletes living with T1D and conducting clinical research was a real privilege,” said Sam, adding that his interest was further piqued by the differences he observed between athletes and people with T1D generally.   

 

Gaps in T1D and exercise knowledge  

In addition to translating and implementing interventions from theory into reality, Sam explained it’s vital to make science comprehensible for healthcare professionals and people living with T1D so they can make sense of what’s known.  

“Seeing different sides of applied strategies or techniques and what was working, what was not, raised a lot of questions for me, like, ‘What’s being done to assist in sports and exercise with type 1 diabetes?”’  

“I realized that many people want to go beyond just incorporating exercise within their lives — and want to know how they can compete at a high level or undertake an endurance event, which would require maximizing sports science, diabetes technology, and diabetes management principles.”  

“My experience highlighted the complexities of combining the challenges of diabetes management and sports science principles to help people reach their individual exercise goals, rather than just getting through a bout of exercise, which was what many people were focused on,” he said.   

 

Tips on fueling for exercise  

Managing T1D while exercising has many complexities — enough to fill an entire book. Here, we’ll concentrate on fueling, just one area of Sam’s varied expertise, to provide practical take-home information.   

“It’s common to find that nutrition information is oversimplified,” explained Sam, but it can vary greatly depending on what sport you’re interested in. “It’s also important to note that the majority of research projects have focused on cycling and running because it’s easier to test these in the lab, so findings may not necessarily apply to basketball or hockey, for example.”  

   

T1D Exchange asked Sam a handful of specific nutrition-related questions — his answers follow.
  

What is fasted exercise, and why does it work?  

The fasted exercise method involves exercising in the morning before breakfast, meaning you will likely have less insulin on board during the exercise.   

What’s the appeal? “There are two aspects that we provide more detail about in the book. The first reason is related to glucose management: If you do fasted exercise, which would normally happen in the morning, there’s less insulin on board,” said Sam. “This way, you won’t be going into an exercise session with extra insulin, which increases the risk of hypoglycemia (low glucose) with the additive effect of muscle contractions.”

“That’s why someone looking for more stable glucose levels during a bout of exercise may try this,” he said. “The second reason to consider fasted exercise might be to elicit a greater training effect.”  

“Some athletes without diabetes opt to do fasted exercise training because there’s evidence it can increase certain adaptations on a molecular level. Meaning, they can hit certain metabolic pathways, improving their response to that exercise.”  

“It can also help with managing weight, which may be particularly important at certain points in a season if you are an athlete or if this is what someone is aiming for,” he said. That’s because fasting exercise helps to burn fat rather than carbohydrates.   

“The potential downside is that without carbohydrates, you’ll find it more difficult to exercise at a higher intensity or longer durations.” In other words, you’ll need carbohydrates to maintain, so understanding the approach based on your goals is important.   

“In one of my first PhD studies, we looked at fasted exercise and compared different types of fasted exercise in people who were recreationally active — meaning average level, non-athletes.”   

“We were interested in this because many people say they prefer exercising in the morning in a fasted state. They say it allows them to exercise for longer (without taking insulin for carbohydrates beforehand), and they find it works well for them,” said Sam, who added that it’s also an approach many clinicians recommend because it’s quite effective.   

 

Let’s talk about the order of exercise. Why does it matter?  

“If you have a general understanding of how certain types of exercise impact your glucose levels, then you can adapt your workout accordingly. For example, generally, high-intensity exercise tends to make glucose levels rise, while longer duration, lower-intensity exercise generally causes glucose levels to decrease.”  

“If you’re going to the gym armed with this information, you could adjust the type of exercise you do rather than opting to adjust insulin or carbohydrates.” Simply put:  

 

 

“It’s about connecting the dots between your glucose and how you can use certain types of exercise as an ‘extra tool,’” so it fits better into your lifestyle.  

“I think when people understand why something happens, they’re more likely to implement it in real life. And rather than needing to refer to resources constantly, it will stick and make sense,” said Sam. “It’s one of the reasons that we wrote our book.”  

 

Why does resistance exercise have different glucose results than cardio?  

Lab-based studies tend to show that lower, moderate-intensity exercise, like jogging or cycling, will cause a reduction in glucose. On the other hand, Sam explained that if you do heavy resistance training such as squats, deadlifts, or other high-intensity, high-energy exercises, you’re likely to see an increase in blood glucose.   

The physiological reason is that certain types of exercise lead to a release of hormones, such as adrenaline, which result in the liver releasing glucose and causing a subsequent rise in blood glucose.   

“There’s a similar mechanism seen with sprinting,” explained Sam. “Again, this is largely taken from lab-based studies, which are small samples, so they don’t necessarily apply to all circumstances.” More research is needed.  

 

How should people with T1D approach fueling for exercise?  

“That’s a hard question, mostly because it’s so multifaceted — and there’s been a tendency to oversimplify fueling for exercise, which is surprisingly complex.”  

In general, with T1D, many people only consider glucose management. It’s actually a “two-sided question,” said Sam. “This is because you’re trying to balance the amount of fuel that you’ll need for a given amount of exercise.” In other words, to fuel for the amount of work required while also trying to balance and support your glucose in the target range.  

Sam explained that their book provides examples for fueling and applying sports science according to a given sport and its level of intensity. You’ll find tables that provide basic suggestions for carbohydrate intake based on the duration and intensity of exercise you’re doing.  

“Conducting research to provide all the answers is incredibly challenging,” said Sam. “Studies are difficult to conduct, costly, and time-consuming, which makes repeated studies looking at a wide variety of sports and other factors difficult, too.”  

“Cycling is where the major focus of general sports nutrition research tends to take place,” so that’s where the most evidence is in terms of fueling for a given intensity.   

 

How can someone living with T1D best tackle exercise and not avoid it?    

“I sympathize with this challenge because when someone doesn’t have type 1 diabetes, they’re able to only focus on fueling,” said Sam. “When someone does have type 1 diabetes, the glucose management side is the most important factor, and then you can consider fueling for the amount of work, second,” said Sam. 

“Consequently, many people under fuel for exercise because they’re trying to avoid high glucose levels.”  

A solid approach is “largely around taking a clear look at your data and trying to figure out what works best for you,” said Sam. “From a glucose management point of view, it can help to develop a plan for the one to two hours leading up to the session and try to aim for a specific glucose target and insulin on board that you feel comfortable with. However, sometimes it’s not possible to plan!”   

“People usually tend to aim for around 7 mmol/L (or 126 mg/dl), but it will depend on your goals, whether it’s a training session, whether it’s competitive, and the intensity of the exercise you’re going into.”  

 

What’s important to highlight when talking about fueling?   

“With our new book, Empowered, we have tried to synthesize information that often gets lost in different sides of conversations,” explained Sam.  

Choosing between different carbohydrates can be confusing for many people because the type and what it’s consumed with can significantly impact glucose levels. “So, we talk about why this is and how the types of carbohydrates are metabolized differently — take fructose versus glucose, for example.”      

This is important to know because many sports supplements use a ratio of two parts glucose to one part fructose to maximize the absorption rate. These supplements are usually developed for endurance sports athletes (who don’t live with diabetes) and aim to help the athlete absorb a high level of carbohydrates to meet high energy demands.  

 

 

 

 

 

 

“Another focus area is on recovery from exercise and understanding the physiology of how your body is refueling after exercise and how some of these mechanisms depend on insulin,” said Sam. There are key windows post-exercise in which you could miss out on refueling opportunities to achieve an optimal state for sports performance.  

When it comes to T1D and exercise, various experiences and considerations are involved, including different environmental factors (weather and elevation) and competitive factors. Thanks to Sam and Simon’s newest book, Empowered: The Science of Exercise with Type 1 Diabetes, people with T1D can benefit from real-world applications of lab-generated exercise science.