Why do hydration and energy balance matter for health and performance?
The importance of hydration and how to maintain it, the factors affecting optimum weight, and the energy balance needed to maintain a healthy weight.
A focused answer to Edexcel GCSE PE on hydration and energy balance: why hydration matters and how to maintain it, the factors affecting optimum weight, how optimum weight varies by sport, and the energy balance needed to maintain a healthy weight.
Reviewed by: AI editorial process; not yet individually human-reviewed
Have a quick question? Jump to the Q&A page
Jump to a section
What this dot point is asking
Edexcel wants you to explain the importance of hydration and how to maintain it, the factors affecting optimum weight, how optimum weight varies by sport, and the energy balance needed to maintain a healthy weight.
Why hydration matters
The effects of dehydration
Optimum weight and the factors affecting it
Optimum weight also varies by sporting role, which the exam likes to test. A sumo wrestler or a rugby prop has a high optimum weight (mass helps them), while a jockey, a gymnast or a long-distance runner has a low optimum weight (lightness helps them). The same height and sex can therefore have very different optimum weights depending on the sport.
Energy balance
Hydrating for the demands of the event
How much a performer drinks depends on the length and intensity of the activity and the conditions. For a short event, water is enough. For a long, sweaty endurance event in the heat, an athlete loses a lot of water and salts through sweat, so a sports drink (containing water, electrolytes and some carbohydrate) replaces the lost fluid and salts and tops up energy, helping to delay dehydration and fatigue. The aim is to drink steadily, before thirst sets in, because by the time you feel thirsty you are already mildly dehydrated and performance has started to drop.
Hydration also links to thermoregulation, the control of body temperature. Sweat cools the body as it evaporates, but the water has to be replaced or the body overheats and the blood thickens. This is why hydration matters most in hot weather and long events, and why a sensible performer plans their drinking around the demands of the activity rather than leaving it to chance.
Exam-style practice questions
Practice questions written in the style of Pearson Edexcel exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
Edexcel 20193 marksExplain why hydration is important during physical activity, and describe two effects of dehydration on performance.Show worked answer →
A Component 2 short-answer question. One mark for the importance, one per effect.
Award marks for: hydration replaces the water lost through sweating, keeps the blood at the right thickness so it can transport oxygen, and helps regulate body temperature. Two effects of dehydration from: the blood thickens so the heart works harder and oxygen delivery falls; body temperature rises (overheating); muscle cramps and fatigue; and reduced concentration and reaction time.
Each effect must show how dehydration harms performance.
Edexcel 20214 marksExplain the energy balance needed to maintain, lose and gain weight, and explain how two factors affect a performer's optimum weight.Show worked answer →
A Component 2 application question, marks for energy balance and factors affecting optimum weight.
Award marks for energy balance: maintaining weight needs energy in (calories eaten) to equal energy out (calories used); a positive energy balance (more in than out) gains weight as fat; a negative energy balance (more out than in) loses weight. Award marks for factors from: sex, height, bone structure and muscle girth (a taller, more muscular performer has a higher optimum weight), and the role in the sport (a sumo wrestler has a high optimum weight, a jockey a low one).
Strong answers explain the three energy states and tie optimum weight to genuine factors.
Related dot points
- The components of a balanced diet, the role of macronutrients and micronutrients, carbohydrate loading and protein timing, and the calculation of BMI.
A focused answer to Edexcel GCSE PE on diet and nutrition: a balanced diet, the role of carbohydrates, proteins, fats, vitamins, minerals, water and fibre, carbohydrate loading and protein timing, and how to calculate and interpret BMI.
- The physical, emotional and social health benefits of participation in physical activity and sport, and how each benefit is achieved.
A focused answer to Edexcel GCSE PE on physical, emotional and social wellbeing: the physical, emotional and social health benefits of participation in physical activity and sport, and how each benefit is achieved.
- A sedentary lifestyle and its consequences (weight, long-term health risks, fitness), and the interpretation of data on trends in physical health issues.
A focused answer to Edexcel GCSE PE on a sedentary lifestyle: the meaning of sedentary, overweight, overfat and obese, the long-term health risks, the impact on fitness, and the interpretation of data on trends in physical health issues.
- Lifestyle choices in diet, activity level, work/rest/sleep balance and recreational drugs, and their positive and negative effects on health and performance.
A focused answer to Edexcel GCSE PE on lifestyle choices: the effects of diet, activity level, the work/rest/sleep balance and recreational drugs (alcohol and nicotine) on health, fitness and wellbeing, including the effects of smoking.
- The short-term effects of exercise on lactate, heart rate, stroke volume, cardiac output and breathing, and how the systems work together to recover.
A focused answer to Edexcel GCSE PE on the short-term effects of exercise: lactate accumulation and muscle fatigue, the rise in heart rate, stroke volume and cardiac output, the change in breathing, and how the systems work together to recover.
Sources & how we know this
- Pearson Edexcel GCSE (9-1) Physical Education (1PE0) specification — Pearson Edexcel (2016)