Proper Hydration for Cyclists

Dehydration is defined as "the excessive loss of water from the body". Dehydration is one of the symptoms of heat exhaustion, which causes an average of 688 deaths annually in the United States.

All heat related illnesses result from the body's inability to dissipate heat more quickly than the body generates heat, resulting in an increase in the body's overall core temperature. Heat related illnesses can be caused by extremely hot temperatures, and/or strenuous exercise resulting in dehydration and salt depletion.

Signs of Dehydration

  • Dizziness
  • Light-headedness
  • Nausea
  • Headaches
  • Muscle cramps
  • Increased body temperature, which can lead to heat exhaustion and death.

Tips for Preventing Dehydration When Cycling


Ride early in the morning, or late in the afternoon when temperatures are cooler. Your body requires less fluid replacement when you exercise in cool weather.


Make sure you are well hydrated before you ride. Most people are chronically dehydrated because they do not drink enough water. Even when you are not exercising, you should keep a bottle of water with you at all times, and sip frequently all day. When you are going to engage in strenuous physical activity, you should drink 16 ounces of a sports drink one hour before you ride. This will provide you with an energy boost, as well as pre-hydrate you. Your sports drink should contain at least 100 mg of sodium per 8 ounces of fluid.


Get use to reaching for water bottles and taking a drink while riding. Evaporative losses can be significant when cycling. Because you are moving fast, the breeze can cause sweat production and fluid loss to go unnoticed. As such, you need to remember to replace fluids during your ride. Make it a habit to drink a few sips of fluid every 15 minutes. If you wear a heart rate monitor, set it to beep every 15 minutes to remind you to drink. Most cyclists require 28 ounces of fluid per hour. However, required consumption can vary, and is dependent on temperature, intensity of the ride, and other many other personal factors. Let experience be your guide.

If you aren't comfortable drinking while riding... practice! Find a parking lot, or other deserted place. Get use to reaching for a water bottle, and taking a drink, while riding. Take one hand off the bar to pull the bottle from the cage. Hold the bar with your other hand near the stem to limit swerving as you reach down. In the alternative, you can look at purchasing hydration packs, which are designed to allow you to drink "hands-free".


Water is fine for short workouts of easy to moderate intensity. But in any workout where sweat losses are substantial, you should drink a sport drink instead of water.

The white stains on your clothing come from the salt that your body sweats out. If you only replace the water lost through sweat, but not the salt lost through sweat, hyponatremia (low concentration of sodium in the blood) can result. Symptoms include nausea, muscle cramps, disorientation, slurred speech, confusion, and inappropriate behavior. As it progresses, you may experience seizures or coma, and eventually death. Severe hyponatremia is considered a medical emergency.

Sport drinks contain dissolved minerals such as sodium, calcium, magnesium, potassium, and phosphate which help fluid to be absorbed into the bloodstream more quickly. In addition to fluid replacement, sport drinks help replenish sodium and other minerals not contained in ordinary drinking water. A new alternative to the traditional sport drinks is "smart water". This is water that has had dissolved minerals added to it. Smart Water is a great alternative to traditional sport drinks for people who do not want the high sugar content of most sport drinks.


When you get off the bike... re-hydrate! No matter how much fluid you drink while riding, you will finish the ride depleted because your stomach cannot empty itself fast enough to keep up with your body's demand for fluid. This is particularly true in hotter weather during more strenuous activity. When you finish riding replace fluids and salt.


Hydration Packs

A hydration pack is back pack or waist pack with a built-in reservoir or "bladder" that allows a cyclist to drink hands-free... great for staying hydrated while cycling.

How to select the right hydration pack for your cycling needs

Hydration packs are designed to carry water and provide storage.  As such, the biggest factor in selecting a hydration pack is the type of cycling you will be doing, and the duration of your ride. Most cyclists require 28 ounces of fluid per hour.

In general- longer rides will require a larger reservoir of water. The amount of room in the pack needed for additional storage will depend on the type of cycling that is being done. If you are touring or riding in the back country off road where access to water and supplies is limited, you will need greater storage and a larger reservoir of water then is needed for urban cycling. Remember: water is heavy (a liter of water weighs approximately 2 pounds) ... the goal is to find the lightest and smallest pack that meets your water and storage requirements in order to limit the weight and bulk.

Choosing the size of the reservoir

1L or 1.5L (34 or 50 fluid ounces): short-distance bike rides and/or riding where refilling reservoirs is convenient.

2L (68 fl. oz.): most popular size because it offers a nice balance of reasonable weight and bulk while providing a sufficient quantity of water,

3L (102 fl. oz.): You are talking almost six pounds of water without even including the weight of your gear. A reservoir this size is only needed for long trips or cycling in areas where refilling the reservoir is not an option.