Low-intensity exercise reduces the prevalence of hyperglycemia in type 2 diabetes.

INTRODUCTION:: Glycemic instability is a severely underestimated problem in type 2 diabetes treatment. Therapeutic targets should aim to reduce postprandial blood glucose excursions. Exercise prescription can effectively improve glucose homeostasis and reduce the risk of cardiovascular complications. AIM:: To assess the impact of a single, isoenergetic bout of low- and high-intensity exercise on the prevalence of hyperglycemia throughout the subsequent 24 h post-exercise period in longstanding type 2 diabetes patients. METHODS:: Nine sedentary, male type 2 diabetes patients (age: 57+/-2 y, BMI: 29.0+/-1.0 kg/m2, Wmax: 2.2+/-0.2 W/kg body weight) were selected to participate in a randomized cross-over study. Subjects performed an isoenergetic bout of endurance type exercise for 60 min at 35%Wmax (LI) or 30 min at 70%Wmax (HI) or no exercise at all (NE). Thereafter, glycemic control was assessed over the subsequent 24 h post-exercise period by continuous glucose monitoring under strict dietary standardization but otherwise free-living conditions. RESULTS:: Average 24 h glucose concentrations were reduced following the low-intensity exercise bout (7.8+/-0.9 mmol/L) when compared with the control experiment (9.4+/-0.8 mmol/L; P<0.05). The high intensity exercise bout did not significantly lower mean glucose concentrations (8.7+/-0.7 mmol/L; P=0.14). Hyperglycemia was prevalent for as much as 35+/-9% throughout the day (NE). A single bout of exercise reduced the prevalence of hyperglycemia by 50+/-4 (P<0.05) and 19+/-9% (P=0.13) in the LI and HI exercise experiment, respectively. CONCLUSION:: A single bout of low-intensity, as opposed to high-intensity, exercise substantially reduces the prevalence of hyperglycemia throughout the subsequent 24 h post-exercise period in longstanding type 2 diabetes patients

Prevalence of daily hyperglycemia in obese type 2 diabetic men compared with that in lean and obese normoglycemic men: effect of consumption of a sucrose-containing beverage.

BACKGROUND: Hyperglycemia forms a direct and independent risk factor for the development of cardiovascular comorbidities in type 2 diabetes. Consumption of sucrose-sweetened soft drinks might further increase the prevalence of hyperglycemic episodes. OBJECTIVE: The objective was to assess glycemic control in type 2 diabetic subjects and healthy lean and obese control subjects under strict dietary standardization but otherwise free-living conditions, with and without the consumption of soft drinks. DESIGN: Obese type 2 diabetic men (n = 11) and lean (n = 10) and obese (n = 10) normoglycemic male control subjects participated in a randomized crossover study. The subjects were provided with a standardized diet in 2 periods, during which they consumed 250 mL water with or without (control) sucrose (37.5 g) 2 h after breakfast and lunch. Blood glucose concentrations were assessed by continuous glucose monitoring. RESULTS: In the type 2 diabetic subjects, the mean 24-h glucose concentrations were significantly elevated (9.1 +/- 0.6 mmol/L), and hyperglycemia (glucose >10 mmol/L) was evident over 33 +/- 8% (8 +/- 2 h) of a 24-h period (P < 0.01). Hyperglycemia was rarely present in the normoglycemic lean and obese control subjects (5 +/- 2%/24 h for both). Consumption of 75 g sucrose, equivalent to 2 cans of a soft drink, did not further augment the prevalence of hyperglycemia throughout the day in any group. CONCLUSIONS: Type 2 diabetic subjects taking oral blood glucose-lowering medication experience hyperglycemia during most of the daytime. Moderate consumption of sucrose-sweetened beverages does not further increase the prevalence of hyperglycemia in type 2 diabetic subjects or in normoglycemic lean or obese men

Intramyocellular lipid and glycogen content are reduced following resistance exercise in untrained healthy males

Resistance exercise has recently been shown to improve whole-body insulin sensitivity in healthy males. Whether this is accompanied by an exercise-induced decline in skeletal muscle glycogen and/or lipid content remains to be established. In the present study, we determined fibre-type-specific changes in skeletal muscle substrate content following a single resistance exercise session. After an overnight fast, eight untrained healthy lean males participated in a approximately 45 min resistance exercise session. Muscle biopsies were collected before, following cessation of exercise, and after 30 and 120 min of post-exercise recovery. Subjects remained fasted throughout the test. Conventional light and (immuno)fluorescence microscopy were applied to assess fibre-type-specific changes in intramyocellular triacylglycerol (IMTG) and glycogen content. A significant 27+/-7% net decline in IMTG content was observed in the type I muscle fibres (P<0.05), with no net changes in the type IIa and IIx fibres. Muscle glycogen content decreased with 23+/-6, 40+/-7 and 44+/-7% in the type I, IIa and IIx muscle fibres, respectively (P<0.05). Fibre-type-specific changes in intramyocellular lipid and/or glycogen content correlated well with muscle fibre-type oxidative capacity. During post-exercise recovery, type I muscle fibre lipid content returned to pre-exercise levels within 120 min. No changes in muscle glycogen content were observed during recovery. We conclude that intramyocellular lipid and glycogen stores are readily used during resistance exercise and this is likely associated with the reported increase in whole-body insulin sensitivity following resistance exercise

Protein co-ingestion strongly increases postprandial insulin secretion in type 2 diabetes patients

The capacity of nutritional protein to induce endogenous insulin secretion has been well established. However, it is not known whether such a response is applicable in a diverse population of type 2 diabetes patients. The aim of the present study was to assess the impact of co-ingesting either intact or hydrolyzed protein with carbohydrate on postprandial plasma insulin and glucose responses in type 2 diabetes patients. Sixty longstanding, male, type 2 diabetes patients participated in a study in which we determined postprandial plasma insulin and glucose responses after ingesting a single bolus of carbohydrate (0.7 g/kg: CHO) with or without an intact protein (0.3 g/kg: PRO) or its hydrolysate (0.3 g/kg: PROh). Results showed that protein co-ingestion strongly increased postprandial insulin release, with the insulin response +99 ± 41 and +110 ± 10% greater in the CHO+PRO and CHO+PROh experiments when compared with the CHO experiment. The insulinotropic properties of protein co-ingestion were evident in nearly all patients, with 58 out of 60 patients responding >10% when compared with the insulin response following carbohydrate ingestion only (CHO). The concomitant plasma glucose responses were 22 ± 32 and 23 ± 36% lower in the CHO+PRO and CHO+PROh experiments, respectively. We conclude that protein co-ingestion represents an effective dietary strategy to strongly augment postprandial insulin release and attenuate the postprandial rise in glucose concentration in type 2 diabetes patients

The muscle protein synthetic response to carbohydrate and protein ingestion is not impaired in men with longstanding type 2 diabetes.

Protein ingestion stimulates muscle protein synthesis and improves net muscle protein balance. Insulin resistance has been suggested to result in a reduced muscle protein synthetic response to food intake. As such, we hypothesized that type 2 diabetes patients have a impaired muscle protein synthetic response to food ingestion. To test this hypothesis, 10 male type 2 diabetes patients using their normal oral glucose-lowering medication (68 +/- 2 y) and 10 matched, normoglycemic men (65 +/- 2 y) were randomly assigned to 2 crossover treatments in which whole body and muscle protein synthesis were measured following the consumption of either carbohydrate (CHO) or carbohydrate with a protein hydrolysate (CHO+PRO). Primed, continuous infusions with L-[ring-13C6]phenylalanine and L-[ring-2H2]tyrosine were applied and blood and muscle samples were collected to assess whole-body protein balance and mixed muscle protein fractional synthetic rate over a 6-h period. Whole-body phenylalanine and tyrosine flux were higher after the CHO+PRO treatment compared with the CHO treatment in the diabetes and control group (P <0.01). Protein balance was negative following CHO but positive following CHO+PRO treatment in both groups. Muscle protein synthesis rates were higher in both groups following the CHO+PRO (0.086 +/- 0.014%/h) treatment than in the CHO treatment (0.040 +/- 0.003%/h; P <0.01) with no difference between the diabetes patients and normoglycemic controls. We conclude that the muscle protein synthetic response to CHO or CHO+PRO ingestion is not substantially impaired in longstanding, type 2 diabetes patients treated with oral blood glucose-lowering medication