EER Calculator – Estimated Energy Requirement
How We Built Our EER Calculator?
When calculating your energy needs for hiking, we use a system based on Metabolic Equivalent of Task (MET) values. This system is widely used in exercise physiology and sports medicine research to quantify the energy cost of physical activities.
What is MET?
A MET represents the ratio of your working metabolic rate to your resting metabolic rate:
- 1 MET = The energy you expend while sitting quietly (approximately 1 calorie per kilogram of body weight per hour)
- Activities are assigned MET values based on their intensity
The Formula We Use
Our calculator uses the following formula to estimate calories burned during hiking:
Calories Burned = MET × Weight (kg) × Duration (hours) × Adjustment Factors
Where:
- MET varies based on hiking intensity:
- Light hiking: 3.8
- Moderate hiking: 5.3
- Strenuous hiking: 7.0
- Extreme hiking/mountaineering: 8.0
- Weight is your body weight in kilograms
- Duration is your hiking time in hours
- Adjustment Factors account for:
- Pack weight (0-15% additional energy)
- Weather conditions (0-12% additional energy)
- Altitude (0-10% additional energy)
- Efficiency gains during extended activity (up to 20% reduction after 4+ hours)
Efficiency Factor for Longer Hikes
Research shows that your body becomes more efficient during prolonged exercise. Our formula includes an efficiency adjustment for hikes longer than 4 hours:
Efficiency Factor = 1.0 – (min(hiking hours – 4, 8) × 0.025)
This means your effective MET value gradually decreases by up to 20% as your body adapts to the sustained activity.
Research Sources
Our MET values are based on established research, including:
- 2011 Compendium of Physical Activities: a second update of codes and MET values – source
- Long-term effect of physical activity on energy balance and body composition – Source
- Energy balance during backpacking – source
While individual factors can cause variations, these research-based values provide reliable estimates for most hikers planning their nutritional needs.
Understanding the Factors That Affect Your Energy Needs
Hiking Intensity
The steepness of the terrain and your pace significantly impact calorie requirements:
- Light hiking (flat terrain, easy pace) burns fewer calories
- Moderate hiking (rolling hills, steady pace) requires more energy
- Strenuous hiking (steep terrain, challenging pace) substantially increases needs
- Extreme mountaineering (technical terrain, heavy load) demands maximum energy
Pack Weight
The heavier your backpack, the more calories you’ll burn:
- Carrying no pack or a day pack (<5 lbs) has minimal impact
- A lightweight pack (5-15 lbs) increases energy needs slightly
- A medium pack (15-30 lbs) noticeably increases calorie burn
- Heavy packs (30-45 lbs) significantly increase energy expenditure
- Expedition packs (45+ lbs) require substantial additional energy
Environmental Conditions
Don’t underestimate how weather and altitude affect your calorie needs:
Weather:
- Cold conditions increase calorie burn as your body works to maintain core temperature
- Extreme heat requires more energy for cooling mechanisms like sweating
- Mild conditions are most energy-efficient
Altitude:
- Higher elevations increase your metabolic rate
- Above 8,000 feet, your body requires significantly more calories
- Very high altitudes (above 12,000 feet) can increase energy needs by 10% or more
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