Nutrition Solutions for Improving Performance in Summer

Sports nutrition can offer a variety of practical solutions to help you perform as best as you can in the warmer months, both in racing and in training. During these periods, athletes think of the obvious things like having icy cold drinks at training and cooling off between repeats, however there are many more things you can do to get the most out of your body over Summer.

Hot weather training makes endurance exercise much harder for a variety of reasons. It is important to recognise all the ways in which we are impaired during exercise in hot weather, so that we can think logically about the best strategies to overcome them. The main ones that should spring to mind are a direct results of increased body temperature. Imagine an assembly line factory in which the 100 workers who work there like the temperature to be between 20 and 25 degrees Celsius. At these temperatures everyone works well together and the assembly line flows well. Now imagine that the aircon breaks and the temperature soars. In the early stages, there may be only 5 complaints and the other 95 workers of the assembly line will have to lift their efforts to make up for the 5 who don’t work well in the warmer environment. As it creeps up, the number of complaints creeps up, and by the time half of the factory are complaining and the other half are working twice as hard to make up for them, the system starts to fail catastrophically.

Your body is exactly like this factory, as your muscles and nervous system operate best within a very narrow range of temperatures (it’s actually around 37degrees Celsius). Even if there is only 10% of your body complaining, such as a calf cramp or some stomach discomfort, the rest of the body now has to work much harder to compensate, and your performance spirals downwards. For every Watt of energy we generate through exercise, we generate 4 Watts of heat, so the harder and longer you exercise, the more likely it is that your body will start to complain. This makes nutritional cooling strategies far more important to a 5km runner when compared to a 100m sprinter.

Dehydration is another factor that drastically reduces performance in the heat. As you lose body fluid and electrolytes, your body cannot transport as much sweat to your skin, and your cooling is reduced, driving body temperature up faster. Fluid loss also means a reduction in blood flow from the heart, which is blood that carries oxygen to the muscles for fuel. A reduction in fuel decreases the work the muscles can do and reduces performance. Your brain function can also be impaired at higher temperatures, as can your pain tolerance and motivation, all of which make high intensity exercise much more difficult. See below for some strategies on how to use sports nutrition to get the most out of your training and racing during the summer.

Strategy 1: Pre-session hydration

Aim: Start session with adequate body fluids and electrolytes.

Why?: Adequate fluids maximise ability to sweat and cool the body and maximise blood volume for best possible delivery of fuel to muscles. Adequate electrolytes allow fluid to move between different compartments of the body to ensure the best possible cooling and oxygen delivery to muscles.

How?: Drink 1 extra sports bottle (600mL) of electrolytes (no carbohydrate) at least 12 hours prior to the session and 300-400mL of sports drink (can be carbohydrate or just electrolytes) about 90 minutes – 2 hours before.

Strategy 2: Pre-session cooling

Aim: Start session at a lower body temperature

Why?: Starting the session at a lower temperature will increase how long you can exercise at peak performance.

How?: Freeze or slushy your pre-session drink. This technique was used by the elite Australian marathoners while training for Beijing Olympics as they consumed a frozen Gatorade about 2 hours before hard sessions.

Strategy 3: Maintaining hydration during the session

Aim: Prevent dehydration in sessions over 60 minutes (warm-up included)

Why?: As you dehydrate, your blood volume decreases and your body temperature increases. Dehydration is also one of the main causes of nausea, bloating, and reflux during exercise, all of which make it harder to fix the issue by taking in more fluids. Basically, if you become very dehydrated, there is no way back!

How?: If you have a high sweat rate or the session is long in duration, taking in 100-150mL of fluid every 30 minutes will reduce the risk of dehydration. Have a water bottle near where you finish your repeats so you can have a sip as soon as you finish to give you the maximum time to let your stomach settle before the next rep.

Strategy 4: Reduce cardiovascular stress and dehydration by avoiding stimulants

Aim: Maximise body fluid and reduce stressors on heart rate

Why? Higher body fluids improve oxygen delivery to the muscles by maintaining blood volume, and reduce cardiovascular stress by reducing how hard your heart works to pump blood around the body.

How?: Restrict caffeine and nitrate intake in very hot conditions as they will improve performance in the short term, but will drastically reduce performance if dehydration occurs. Also, stick to your prescribed running pace to keep your heart rate within manageable ranges.

Ideally, if you have identified one or two sessions per week that are performed in very high heat conditions, you should aim to implement all of these strategies to get the best training performance. If you want to know more, feel free to send me an email at alex@catalystdietitian.com.au

Alex Dreyer

Sports Dietitian & Athletics Australia Coach