Low-Volume High-Intensity Interval Training as a Therapy for Type 2 Diabetes.

Our purpose was to investigate the effects of low-volume, high-intensity interval training (HIT) on cardiometabolic risk and exercise capacity in women with type 2 diabetes mellitus (T2DM). Sedentary overweight/obese T2DM women (age=44.5±1.8 years; BMI=30.5±0.6 kg/m(2)) were randomly assigned to a tri-weekly running-based HIT program (n=13) or non-exercise control follow-up (CON; n=10). Glycemic control, lipid and blood pressure levels, endurance performance, and anthropometry were measured before and after the follow-up (16 weeks) in both groups. Medication intake was also assessed throughout the follow-up. Improvements (P<0.05) on fasting glucose (14.3±1.4%), HbA1c (12.8±1.1%), systolic blood pressure (3.7±0.5 mmHg), HDL-cholesterol (21.1±2.8%), triglycerides (17.7±2.8%), endurance performance (9.8±1.0%), body weight (2.2±0.3%), BMI (2.1±0.3%), waist circumference (4.0±0.5%) and subcutaneous fat (18.6±1.4%) were found after HIT intervention. Patients of HIT group also showed reductions in daily dosage of antihyperglycemic and antihypertensive medication during follow-up. No changes were found in any variable of CON group. The HIT-induced improvements occurred with a weekly time commitment 56-25% lower than the minimal recommended in current guidelines. These findings suggest that low-volume HIT may be a time-efficient intervention to treat T2DM women.

Rating of perceived exertion as a tool for prescribing and self regulating interval training: a pilot study.

The aim of the present study was to analyse the usefulness of the 6-20 rating of perceived exertion (RPE) scale for prescribing and self-regulating high-intensity interval training (HIT) in young individuals. Eight healthy young subjects (age = 27.5±6.7 years) performed maximal graded exercise testing to determine their maximal and reserve heart rate (HR). Subjects then performed two HIT sessions (20 min on a treadmill) prescribed and regulated by their HR (HR: 1 min at 50% alternated with 1 min at 85% of reserve HR) or RPE (RPE: 1 minute at the 9-11 level [very light-fairly light] alternated with 1 minute at the 15-17 level [hard-very hard]) in random order. HR response and walking/running speed during the 20 min of exercise were compared between sessions. No significant difference between sessions was observed in HR during low- (HR: 135±15 bpm; RPE: 138±20 bpm) and high-intensity intervals (HR: 168±15 bpm; RPE: 170±18 bpm). Walking/running speed during low- (HR: 5.7±1.2 km · h(-1); RPE: 5.7±1.3 km · h(-1)) and high-intensity intervals (HR: 7.8±1.9 km · h(-1); RPE: 8.2±1.7 km · h(-1)) was also not different between sessions. No significant differences were observed in HR response and walking/running speed between HIT sessions prescribed and regulated by HR or RPE. This finding suggests that the 6-20 RPE scale may be a useful tool for prescribing and self-regulating HIT in young subjects.

Effects of high-intensity interval vs. continuous moderate exercise on intraocular pressure.

Our purpose was to compare the acute effects of high-intensity interval training (HIT) vs. continuous moderate exercise (CME) on intraocular pressure (IOP) in healthy subjects. Fifteen young men (age=22.1±6 years) underwent 30 min of HIT (2 min of walking at 50% of reserve heart rate (HR) alternated with 1 min of running at 80% of reserve HR) and CME sessions (30 min of jogging/running at 60% of reserve HR) in random order (2-5 days between sessions). IOP was measured before (baseline), immediately after (post--exercise), 5 min after (Rec5) and 10 min after (Rec10) each exercise session. IOP was reduced post-exercise and remained reduced at Rec5 during both HIT and CME session, with no significant difference between interventions (~16% between 23%). However, IOP remained reduced at Rec10 only after HIT intervention (~19%), whereas IOP at Rec10 returned to levels similar to the observed at baseline during CME intervention. In summary, both HIT and CME equally reduced IOP immediately and 5 min after exercise session. However, only HIT was able to remain IOP reduced 10 min after exercise. These results suggest that HIT may be more effective than CME for reducing IOP in young healthy men.

Age affects exercise-induced improvements in heart rate response to exercise.

The aim of the present study was to analyze the effects of age on cardiorespiratory fitness (CRF), muscle strength and heart rate (HR) response to exercise adaptation in women in response to a long-term twice-weekly combined aerobic and resistance exercise program. 85 sedentary women, divided into young (YG; n=22, 30.3 ± 6.2 years), early middle-aged (EMG; n=28, 44.1 ± 2.5 years), late middle-aged (LMG; n=20, 56.7 ± 3.5 years) and older (OG; n=15, 71.4 ± 6.9 years) groups, had their CRF, muscle strength (1-repetition maximum test) and HR response to exercise (graded exercise test) measured before and after 12 months of combined exercise training. Exercise training improved CRF and muscle strength in all age groups (P<0.05), and no significant differences were observed between groups. Exercise training also improved resting HR and recovery HR in YG and EMG (P<0.05), but not in LMG and OG. Maximal HR did not change in any group. Combined aerobic and resistance training at a frequency of 2 days/week improves CRF and muscle strength throughout the lifespan. However, exercise-induced improvements in the HR recovery response to exercise may be impaired in late middle-aged and older women.

Resistance exercise intensity progression in older men.

Our purpose was to examine possible influences of age on resistance exercise (RE) intensity progression in men. Twenty-four men, divided in young sedentary (YS; n=10; 25.9+/-3.7 years), older sedentary (OS; n=7; 67.4+/-5.2 years), and older runners (OR; n=7; 71.3+/-3.0 years), underwent a 2 times-a-week RE program for 13 weeks. Muscle strength was assessed before and after training by 1-repetition maximum test. RE workloads were recorded for each exercise session, and increases of 5-10% were made whenever adaptation occurred. Muscle strength improved similarly in all groups after RE (P<0.001). Relative RE intensity progression was not significantly different between YS and OS, except for a greater increase in calf raise relative workload observed in YS (P<0.05). In contrast, OR displayed greater relative workload increase in 7 and 6 exercises than YS and OS, respectively (P<0.05). The RE was safe as no injuries or major muscle pain were observed in either group. These results suggest that healthy sedentary older men are capable to exercise and increase RE intensity in the same way as young men, while physically active older men are capable to increase RE intensity in greater way than sedentary young and older men.

Haemodynamic, metabolic and neuro-humoral abnormalities in young normotensive women at high familial risk for hypertension.

We analysed the haemodynamic, metabolic and hormonal status at rest and in response to exercise, in young normotensive women with two hypertensive parents (FH++; n=17; 25.1±4.8 years), one hypertensive parent (FH+; n=18; 24.9±4.1 years) and normotensive parents (FH-; n=15; 25.3±3.8 years). Casual and ambulatorial blood pressure (BP), carotid-femoral pulse wave velocity (PWV) and biochemistry were analysed. BP, nor-epinephrine (NE), epinephrine (EPI), endothelin-1 (ET-1) and nitrite/nitrate (NOx) levels were also analysed during a graded exercise test (GXT). Casual and ambulatorial BP were not different between groups, but PWV was 7.5 and 12.6% higher in FH++ than FH+ and FH-, respectively, and 4.8% higher in FH+ than FH- (P≤0.01). Insulin and insulin-to-glucose ratio were increased in FH++ and FH+ (P<0.05), and low-density lipoprotein (LDL)-cholesterol tended to be higher only in FH++ (P=0.07). FH++ showed higher exercise and recovery diastolic BP and EPI levels, and increased resting, exercise and recovery NE, and ET-1 levels than FH- (P<0.05). FH+ showed only greater resting, exercise and recovery NE, and rest ET-1 (P<0.05). Resting, exercise and recovery NOx were lower in FH++ and FH+ than FH- (P<0.01). Haemodynamic, metabolic and hormonal abnormalities were presented in nonhypertensive young women offspring of hypertensive parents before any increase in BP. Greater abnormalities were observed in women with a strong family history of hypertension (FH++). These results suggest that there is an early vascular, metabolic and hormonal involvement in a familial hypertensive disorder.