Being overweight can affect the health and life expectancy of a person - AQA - GCSE Biology Combined Science - Question 3 - 2020 - Paper 1

To find the height, we use the formula:
$\text{BMI} = \frac{\text{body mass in kg}}{(\text{height in m})^2}$
Substituting the values given:
$27 = \frac{68.1}{(\text{height})^2}$
Rearranging gives:
$(\text{height})^2 = \frac{68.1}{27}$
Calculating, this results in:
$\text{height} = \sqrt{\frac{68.1}{27}} = 1.59 \text{ m}$.

The woman is categorized as overweight according to the BMI and body mass chart.

The balance between the mass of food consumed and physical activity determines body mass.

• When energy intake from food exceeds energy expenditure through exercise, the body stores the excess as fat, leading to weight gain.
• Conversely, if a person consumes less energy than they expend, they will lose weight.
• Thus, a healthy balance of diet and exercise is crucial for maintaining an ideal body mass.

During vigorous exercise, several physiological changes occur:

1. Increased Breathing Rate: The need for oxygen escalates, leading to quicker breathing.
2. Elevated Heart Rate: The heart pumps faster to supply more blood (and oxygen) to the muscles.
3. Increased Blood Flow to Muscles: Blood is directed towards muscles requiring more oxygen.
4. Anaerobic Respiration: If the oxygen supply is insufficient, the body might switch to anaerobic metabolism producing lactic acid.
   Post-exercise, the body gradually returns to its resting state:

• Heart rate and breathing rate decrease.
• Oxygen levels normalize as the body works to remove lactic acid and replenish oxygen levels.