INSIDE SPORTS NUTRITION

Cold weather – you either love it or you don’t. While it can be a relief to not worry about heat stress, let’s discuss how cold weather can affect your body and exercise.
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→ Voluntary dehydration: You may not feel as thirsty so there can be a tendency to neglect fluids during exercise. It’s also easy to neglect fluids if you don’t keep them accessible, which can be challenging when you’re wearing big gloves and/or wearing/carrying a lot of additional gear.

→ Diuresis: Cold temperatures cause peripheral blood vessels to constrict so that blood flow can be directed to organs. Subsequently, diuresis occurs in response to the rise in blood pressure, causing frequent urge to pee and increased water and sodium losses in the urine.

→ Shivering: It’s an involuntary mechanism to keep the body warm by producing heat. Shivering increases oxygen consumption and glycogen use; but, this typically occurs mainly at the beginning/end of a cold training session as long as you are dressed appropriately for the weather.

→ Sweating: When excessive clothing is worn relative to the exercise intensity and duration, sweat losses can increase, resulting in wet clothing and possible hypothermia. For this reason, it’s recommended to dress in layers and remove layers as metabolic rate and heat losses increase. Clothing choices that are highly breathable, wicking, and provide some insulation are the best options to use when layering. Interestingly, some research suggests females may be more tolerant to cold compared to similarly fit males, evidenced by the ability to maintain performance during short duration, intense exercise performance when they wear insulative high performance clothing. On the other hand, if female athletes are overdressed for the conditions, they may also be more prone than males to shivering due to excessive sweating. Ultimately, the importance of proper clothing and warm-up strategy is important and may be slightly different for males and females.

TAKEAWAYS:
In colder temperatures:
Prioritize hydration ➡️
Consume beverages containing sodium to help retain fluids (e.g. Warm tea with honey and a pinch salt, a sports drink, or broth)

Develop a hydration plan based on estimated sweat rates in the cold and keep fluids accessible
Rehydrate after exercise with 20-24 oz per pound lost

Dress appropriately and have an adequate warm-up protocol ➡️
Dress in layers and shed them as you warm up
Your warm-up strategy should aim to increase muscle temperature and avoid excessive shivering.

Fuel to meet energy demands ➡️
Eat before exercise to top off glycogen stores
Consume warm foods/ beverages pre and post exercise (e.g. Oatmeal, soup, hot cocoa)
Ingest carbs during exercise (30-60 grams/hour) for endurance activity lasting > 60 minutes or 90-120 grams/hour for longer, more intense training or competition. Pack additional snacks if going on an adventure where duration may be questionable.
Ingest carbs as soon as possible after exercise (1-1.2 grams per kg), to restore glycogen.
Increase fuel intake if you are shivering due to any reason.

PMID: 22649525; 26891166, 34574624