Physical activity is a huge part of Ashley Charlebois’s daily life. The registered dietitian commutes by bike, cycling 40 minutes to and from work. She gets there early so she can do weights at the on-site gym before she starts seeing clients. Then, in the evenings, she’ll either play soccer, Ultimate, or do a local hike, like the ever-popular Grouse Grind.
“I’ve always been active my whole life,” Charlebois says on the line from Burnaby’s Fortius Sport & Health, where she works. “I started realizing more and more the connection how food affects activity levels in my own sports. Proper nutrition can be a huge benefit in performance.”
One of the most common mistakes people make, she says, is not being adequately hydrated. Whether they’re hiking in Garibaldi Park on a sunny summer Saturday, doing a group fitness class, or playing tennis, people tend to overlook just how much fluid intake they need and when.
“You need to stay hydrated before, during, and after a workout,” says Charlebois, who is also a certified exercise physiologist. “A lot of people will start out dehydrated, then they’re just even more dehydrated throughout the day.”
Dehydration negatively affects exercise performance in a number of ways, according to the second edition of Sport Nutrition: An Introduction to Energy Production and Performance. Authors Asker Jeukendrup and Michael Gleeson explain that inadequate hydration results in decreased blood volume, sweat rate, and heat dissipation as well as increased core temperature and rate of muscle glycogen use. Anyone who exercises regularly is susceptible to the effects of even mild dehydration. Athletic performance is impaired when someone is dehydrated by as little as two percent of her body weight, and a loss greater than five percent of a person’s body weight can decrease the capacity for work by about 30 percent.
As a person becomes increasingly dehydrated, symptoms include difficulty concentrating, loss of endurance capacity, increased effort required for exercise, increased pulse rate, vague physical discomfort, apathy, sleepiness, tingling sensations, stumbling, laboured breathing, headache, dizziness, mental confusion, muscle spasms, loss of balance, and increased overall weakness. Severe dehydration can lead to heat exhaustion, heat stroke, delirium, difficulty swallowing, and loss of consciousness or even death.
Naturally, people who exercise must drink plenty of water. Although water replenishes fluids lost during physical activity, it doesn’t replace the minerals that the body loses via sweating. Perspiration releases potassium, sodium, and calcium, which are critical for human survival. Also known as electrolytes, these minerals aren’t found in water.
That’s why there’s such a huge market for sports drinks. However, Charlebois says it’s simple (and more economical) to make your own. She shares her recipe:
Homemade sports drink
½ L any 100-percent pure fruit juice
½ L water
1/3 tsp. salt
Charlebois likes mixed-berry juice, but any will do, as long as it’s pure juice and not a fruit “punch” or “cocktail”, which consist mainly of sugar. She also recommends reading ingredient labels: some sports drinks consist of excessive amounts of sugar as well as preservatives, artificial flavours, and food colourings or dyes.
“That [homemade sports drink ] is going to provide carbohydrates from the fruit juice, potassium from the fruit juice, and sodium from the salt,” Charlebois says. “Potassium and sodium are two electrolytes that we lose in highest quantities in our sweat when we exercise.”
Coconut water is an increasingly popular postworkout drink. It is high in potassium and carbohydrates, but lacks sodium, Charlebois notes.
When it comes to rehydrating, timing is everything. The body needs to replenish within 30 minutes of physical activity.
“There’s a half-hour window after you stop exercise that your body can absorb glucose and convert it into stored form at the fastest rate, storing it into muscle for energy for later use,” Charlebois says. “It’s really important right after you finish exercise that you…get something that’s high in carbohydrates, because that’s the only nutrient that’s broken down right away into glucose, which is your body’s primary source of energy during activity. Right after exercise, you want to rehydrate and you also want to refuel. You want something high in carbs and you want a little protein as well.” The protein will help the body absorb carbohydrates and repair any muscle-tissue damage.
“There are common misconceptions, though,” she adds. “You’ll see a lot of guys in the gym drinking protein shakes, for example, thinking that that’s going to build their muscles….Protein isn’t as time-sensitive as carbohydrates are.”
Of course, carbs have gotten a bad rap with the popularity of low- or no-carb diets, but that’s another common source of confusion, Charlebois says.
“It’s a trend to avoid carbs, but carbs are the most efficient source of energy for us, and there are different types of carbs,” she explains. “Vegetables and fruits count as carbohydrates; so do certain grain products and dairy products. You want to avoid simple sugars and simple carbohydrates, but things like whole grains—brown rice, quinoa, brown bread—those are good options. They have a lot of fibre and they have a lot of B vitamins. It's really hard to fuel properly without them [carbs] and to meet all your nutrient needs. It’s about portion control and getting right types of carbohydrates.”
If you’re exercising for longer than 60 minutes, you’ll also need to replenish throughout. “The body will start to fatigue unless you reenergize it with a bit more carbs; you’re also losing electrolytes. So to combat that fatigue, have that sports drink on hand, about a litre, and start taking a few sips starting about 45 minutes into your workout. That’s going to help fuel you longer.”
A few ideas for postexercise snacks include fruit, a handful of raw almonds or walnuts, or a fruit smoothie made with ingredients such as frozen berries, yogurt, peanut butter, kale… The list goes on.
“If you don’t hydrate and refuel properly, the body’s not going to recover,” Charlebois says. “And remember to drink lots of water throughout the day.”