Mini Marathon Training Advice - Clinical Nutrition 3

Here is the second blog the Department of Clinical Nutrition have provided in a series designed to help all our participants prepare for this year's mini marathon. We hope you enjoy the series, which also includes blogs from Physiotherapist Julie Jordan.

Fluids – Hydration is the key to success!

By Orla Haughey and Suzanne Seery, Clinical Nutritionists, St James’s Hospital

Exercise is thirsty work! Whenever you exercise you lose fluid, not only through sweating but also as water vapour in the air that you breathe out.  In warmer weather, fluid losses are increased. When you are dehydrated your muscles don’t work as well, exercise feels tougher, you feel tired quicker and you cannot train at your best.

When and how much to drink before starting exercise?

The best strategy is to keep hydrated throughout the day rather than load up with fluid just before your training session.

• Drink water regularly throughout the day, carry a bottle of water with you as a reminder
• In the 2 hours before exercising aim to drink 400-600mls, this promotes hydration and allows enough time for excretion of excess water from the body.
• Limit alcohol and caffeine drinks (e.g. tea, coffee, caffeinated fizzy drinks) before exercising as they can have a dehydrating effect.

During Exercise:

• It is important to drink during exercise that lasts more than 1 hour, especially in warm weather.
• Drinking little and often, according to your thirst, during exercise.  About 150-200mls (a small glass) every 15-20mins is a rough guide to the volume.
• A good tip is to practice drinking fluids while exercising before the race so your body can become used to it.

After Exercise:

• It is important to drink fluids immediately after exercise to restore the fluids lost while sweating and prevent dehydration.
• Try to drink around 500mls in the first 30 minutes. Sipping little and often rather than guzzling down all in one go, will hydrate you better.
• The amount of fluid needed will depend on the duration of exercise and the amount of fluid lost while sweating. As a general guide, keep sipping until you are passing clear or pale urine.

What type of fluids should I drink?

Water is a good choice if exercising for an hour or less. For longer or higher intensity exercise sessions, drinks containing carbohydrate and some sodium are good (e.g. isotonic sports drink).  An Isotonic drink has the same number of dissolved particles (osmolarity) e.g. electrolytes and carbohydrates, as are found in our blood plasma. Isotonic drinks help replace energy stores and salt losses from sweat and aid hydration.

Before and during exercise:

• Water
• Isotonic sports drink e.g. Lucozade, Powerade, Gatorade

After exercise:

• Milk
• Isotonic sports drink,
• Soft drinks (Not diet versions)
• Fruit Juice

For a cheaper alternative to commercial isotonic sports drinks, why not try this homemade version.

Mix together:

200mls of Fruit cordial

800mls of water

Pinch of salt

Contact Us

St. James’s Hospital Foundation
St. James’s Hospital
James’s Street
Dublin 8

Telephone 01 428 4086
Email foundation@stjames.ie