Sugar provides energy but does not combat stress, scientists have found

Scientists from the University of Konstanz have found that sugar consumption increases sympathetic nervous system activity and prevents the body from fully relaxing, despite the subjective feeling of rest. The results of the study were published in the journal Nutrients.

The experiment involved 94 healthy adults. Some participants fasted before visiting the laboratory, after which one group was given a glucose drink while the other received water. Half of the participants received a relaxing massage, while the rest simply rested.

The researchers continuously monitored cardiac activity indicators, including heart rate variability and pre-ejection periods, which reflect the functioning of the parasympathetic and sympathetic nervous systems.

The results showed that massage or rest activated the parasympathetic system, responsible for relaxation, regardless of sugar intake.

"However, after glucose consumption, the sympathetic system was simultaneously activated — the one that maintains the body's heightened readiness and stress response. This suggests that although a person may feel calm, the body remains in a state of heightened arousal," the researchers clarified.

The scientists explain that sugar helps briefly mobilize energy to cope with stressful episodes but simultaneously reduces the body's ability to fully relax. Prolonged frequent consumption of sweets, according to the specialists, may increase the risks of hypertension, obesity, and cardiovascular diseases.