Functional high-intensity training improves pancreatic β-cell function in adults with type 2 diabetes

Abstract

Type 2 diabetes (T2D) is characterized by reductions in β-cell function and insulin secretion on the background of elevated insulin resistance. Aerobic exercise has been shown to improve β-cell function, despite a subset of T2D patients displaying "exercise resistance." Further investigations into the effectiveness of alternate forms of exercise on β-cell function in the T2D patient population are needed. We examined the effect of a novel, 6-wk CrossFit functional high-intensity training (F-HIT) intervention on β-cell function in 12 sedentary adults with clinically diagnosed T2D (54 ± 2 yr, 166 ± 16 mg/dl fasting glucose). Supervised training was completed 3 days/wk, comprising functional movements performed at a high intensity in a variety of 10- to 20-min sessions. All subjects completed an oral glucose tolerance test and anthropometric measures at baseline and following the intervention. The mean disposition index, a validated measure of β-cell function, was significantly increased (PRE: 8.4 ± 3.1, POST: 11.5 ± 3.5, = 0.02) after the intervention. Insulin processing inefficiency in the β-cell, expressed as the fasting proinsulin-to-insulin ratio, was also reduced (PRE: 2.40 ± 0.37, POST: 1.78 ± 0.30, = 0.04). Increased β-cell function during the early-phase response to glucose correlated significantly with reductions in abdominal body fat ( = 0.56, = 0.005) and fasting plasma alkaline phosphatase ( = 0.55, = 0.006). Mean total body-fat percentage decreased significantly (Δ: -1.17 0.30%, = 0.003), whereas lean body mass was preserved (Δ: +0.05 ± 0.68 kg, = 0.94). We conclude that F-HIT is an effective exercise strategy for improving β-cell function in adults with T2D.

Functional high‐intensity exercise training ameliorates insulin resistance and cardiometabolic risk factors in type 2 diabetes

“…Notably, android fat ( P < 0.05), gynoid fat ( P < 0.01), trunk fat ( P < 0.05) and leg fat ( P < 0.0001) were all decreased, while lean tissue remained unchanged. Aerobic fitness () was increased after the F‐HIT training programme (Nieuwoudt et al., ). The 6‐week exercise intervention also resulted in a decrease in DBP ( P < 0.01) and mean arterial pressure (MAP; P < 0.05).…”

“…We recruited 13 overweight/obese, sedentary adults (5 males, 8 females; age 53 ± 7 years; BMI 34.5 ± 3.6 kg m −2 ; mean ± SD) with clinically diagnosed non‐insulin‐dependent T2D from the local community. This dataset includes 12 participants that were described in a previous publication examining the effect of F‐HIT on pancreatic β‐cell function in individuals with T2D (Nieuwoudt et al., ). All participants were screened with a medical history and physical examination, blood and urine chemistry analyses, and a resting and exercise stress test with 12‐lead electrocardiogram.…”

“…Over the course of 6 weeks, subjects were exposed to an array of functional weightlifting, gymnastics and endurance movements in various combinations such as deadlifts, clean and snatch, overhead press, gymnastic style ring exercises, box jumps, and body weight exercises. All subjects completed the same workouts, but no individual sessions were replicated – with the exception of sessions 2 and 18 which were used as a measure of functional improvement (Nieuwoudt et al., ). Examples of specific workouts are described in Table .…”

The essential role of exercise in the management of type 2 diabetes

“…Our proof-of-concept study found that a 6-week CrossFit program reduced body fat, diastolic blood pressure, lipids, and metabolic syndrome Z-score, and increased insulin sensitivity to glucose, basal fat oxidation, VO 2max , and high-molecular-weight adiponectin. 30 HIIT appears to be another effective way to improve metabolic health; and for patients with type 2 diabetes who can tolerate HIIT, it may be a time-efficient, alternative approach to continuous aerobic exercise.…”

“…55 And we recently found that a 6-week CrossFit training program improved beta-cell function in adults with type 2 diabetes. 30 …”