A single 30-minute bout of aerobic exercise significantly reduced both fasting and 1-hour post load plasma glucose levels in healthy young adults, according to a new study. The findings suggest that even occasional exercise could help improve insulin sensitivity and glucose metabolism. 

In the study, published in the Journal of Endocrinological Investigation, included 32 participants (14 women and 18 men) aged 20 to 35 years with normal or marginally elevated body mass index (BMI) (18 to 28 kg/m²). None of the participants were competitive athletes or receiving medications, and all of them had normal fasting blood glucose levels (< 100 mg/dL). 

The participants underwent baseline oral glucose tolerance tests (OGTT) after 4 days of physical inactivity. Seven days later, they performed a single 30-minute light jogging session monitored via metabolic hoster. A second OGTT was administered 24 hours postexercise.

The exercise session averaged:

• Duration: 32 ± 15 minutes
• Intensity: 6.9 ± 1.5 METs
• Total energy expenditure: 365 ± 125 kcal
• Active energy expenditure: 352 ± 106 kcal.

The researchers found that after just 1 exercise session, the participants showed decreased glucose levels at baseline (82.8 ± 5 mg/dL vs 78.5 ± 7 mg/dL, P = .002) and at 1 hour following an OGTT (122.8 ± 34 mg/dL vs 111.8 ± 25 mg/dL, P = .03).

Beyond glucose improvements, insulin levels were significantly lower 1-hour post load glucose following exercise (57.4 ± 37 μUI/mL vs 43.5 ± 19 μUI/mL, P = .01).

The researchers also observed a trend toward increased beta-cell function via HOMA-B (144.7 ± 70 vs 167.1 ± 133); however, this did not reach statistical significance.

The study's findings were particularly relevant given that elevated 1-hour glucose levels during OGTT (> 155 mg/dL) were associated with an increased risk of type 2 diabetes and cardiovascular complications. The demonstrated improvements in 1-hour post load glucose following a single exercise session suggested potential preventive benefits.

The researchers noted this was one of the first studies to specifically evaluate the effect of a single exercise bout on 1-hour post load plasma glucose in healthy, untrained individuals.

Study limitations include the small sample size and lack of C-peptide measurements, which could have provided additional insights into insulin secretion patterns. The researchers emphasized that modifications in beta-cell secretory capacity during exercise were likely secondary to improved insulin action in insulin-dependent tissues.