Introduction
This topic covers how diet should be adjusted for people who work under harmful or demanding conditions (heat, heavy physical load, chemical and dust exposure, noise, ionizing radiation, shift work) and for people under chronic or acute psychological stress. A good answer explains the physiological basis of each situation, the specific nutritional needs it creates, and the practical recommendations for workers and for those who organise their work and meals.
Nutrition in hot and physically heavy work
Work in a hot microclimate (foundries, bakeries, glass production, agriculture in summer, mining) and heavy physical work raise energy expenditure and cause large losses of water and electrolytes through sweat. Sweat can reach 1 to 1.5 litres per hour during intense work in heat, and it contains sodium, potassium, chloride and some magnesium. The main nutritional aim is to prevent dehydration, heat exhaustion and heat cramps, and to cover the increased energy need.
- Drink water regularly during the shift, in small portions (about 150 to 250 ml every 15 to 20 minutes), rather than large volumes at once.
- During prolonged sweating (more than about one hour of heavy work in heat), use drinks or meals with sodium and other electrolytes, because plain water alone can dilute blood sodium.
- Check urine colour as a simple guide to hydration; pale yellow urine indicates adequate intake.
- Energy intake must match the work category; heavy manual work may require 3000 kcal per day or more, so the diet should contain enough complex carbohydrates and fats for sustained effort.
- Alcohol, strong coffee and energy drinks should be avoided before and during work in heat, as they increase fluid loss and impair thermoregulation and judgement.