O'Connor E, Kiely C, O'Shea D, Green S, Egaña M. Similar level of impairment in exercise performance and oxygen uptake kinetics in middle-aged men and women with type 2 diabetes. Am J Physiol Regul Integr Comp Physiol 303: R70 -R76, 2012. First published April 25, 2012 doi:10.1152/ajpregu.00012.2012.-The present study tested the hypothesis that the magnitude of the type 2 diabetes-induced impairments in peak oxygen uptake (V O2) and V O2 kinetics would be greater in females than males in middle-aged participants. Thirty-two individuals with type 2 diabetes (16 male, 16 female), and 32 age-and body mass index (BMI)-matched healthy individuals (16 male, 16 female) were recruited. Initially, the ventilatory threshold (VT) and peak V O2 were determined. On a separate day, subjects completed four 6-min bouts of constant-load cycling at 80% VT for the determination of V O2 kinetics using standard procedures. Cardiac output (CO) (inert gas rebreathing) was recorded at rest, 30, and 240 s during two additional bouts. Peak V O2 (ml·kg ). The time constant (s) of phase 2 (2) and mean response time (s) of the V O2 response (MRT) were slowed in women with type 2 diabetes compared with healthy women (2, 43.3 Ϯ 9.8 vs. 33.6 Ϯ 10.0 s; MRT, 51.7 Ϯ 9.4 vs. 43.5 Ϯ 11.4s) and in men with type 2 diabetes compared with nondiabetic men (2, 43.8 Ϯ 12.0 vs. 35.3 Ϯ 9.5 s; MRT, 57.6 Ϯ 8.3 vs. 47.3 Ϯ 9.3 s). The magnitude of these impairments was not different between males and females. The steady-state CO responses or the dynamic responses of CO were not affected by type 2 diabetes among men or women. The results suggest that the type 2 diabetes-induced impairments in peak V O2 and V O2 kinetics are not affected by sex in middle aged participants. cycling; sex; cardiac output MAXIMAL AEROBIC CAPACITY, expressed as maximum oxygen uptake (V O 2 ), which is an independent risk factor for all-cause and cardiovascular disease mortality (27) has been consistently reported to be reduced in individuals with type 2 diabetes compared with nondiabetic counterparts of similar age, weight, and activity levels (8,17,32). Additionally, the rate of adjustment of oxygen uptake (V O 2 kinetics) to steady-state exercise is slower in young and middle-aged women (8, 21, 32) and in a combined group of middle-aged men and women (4), although recent data suggests that V O 2 kinetics are not impaired in older men with type 2 diabetes compared with age-matched healthy controls (42). The slowing of the V O 2 kinetic response is associated with a faster onset of fatigue and lower exercise tolerance (28) and might help explain why individuals with type 2 diabetes perceive light/moderate exercise as more difficult than healthy controls (12). Ultimately this often leads to a sedentary behavior or physical inactivity, which is associated with worsening of cardiovascular outcomes and predicts mortality in people with type 2 diabetes (6, 39). The mechanisms underpinning these exercise impairments in younger and middle-aged individuals with type 2 diabetes have not been...

We investigated if the magnitude of the type 2 diabetes (T2D)-induced impairments in peak oxygen uptake (V̇o2) and V̇o2 kinetics was affected by age. Thirty-three men with T2D (15 middle-aged, 18 older), and 21 nondiabetic (ND) men (11 middle-aged, 10 older) matched by age were recruited. Participants completed four 6-min bouts of constant-load cycling at 80% ventilatory threshold for the determination of V̇o2 kinetics. Cardiac output (inert-gas rebreathing) was recorded at rest and 30 and 240 s during two additional bouts. Peak V̇o2 (determined from a separate graded test) was significantly (P < 0.05) reduced in middle-aged and older men with T2D compared with their respective ND counterparts (middle-aged, 3.2 ± 0.5 vs. 2.5 ± 0.5 l/min; older, 2.7 ± 0.4 vs. 2.4 ± 0.4 l/min), and the magnitude of these impairments was not affected by age. However, the time constant of phase II of the V̇o2 response was only slowed (P < 0.05) in middle-aged men with T2D compared with healthy counterparts, whereas it was similar among older men with and without T2D (middle-aged, 26.8 ± 9.3 vs. 41.6 ± 12.1 s; older, 40.5 ± 7.8 vs. 41.1 ± 8.5 s). Similarly, the "gains" in systemic vascular conductance (estimated from the slope between cardiac output and mean arterial pressure responses) were lower (P < 0.05) in middle-aged men with T2D than ND controls, but similar between the older groups. The results suggest that the mechanisms by which T2D induces significant reductions in peak exercise performance are linked to a slower dynamic response of V̇o2 and reduced systemic vascular conductance responses in middle-aged men, whereas this is not the case in older men.

Kiely C, O'Connor E, O'Shea D, Green S, Egaña M. Hemodynamic responses during graded and constant-load plantar flexion exercise in middle-aged men and women with type 2 diabetes. J Appl Physiol 117: 755-764, 2014. First published August 14, 2014 doi:10.1152/japplphysiol.00555.2014.-We tested the hypotheses that type 2 diabetes (T2D) impairs the 1) leg hemodynamic responses to an incremental intermittent plantar-flexion exercise and 2) dynamic responses of leg vascular conductance (LVC) during low-intensity (30% maximal voluntary contraction, MVC) and high-intensity (70% MVC) constant-load plantar-flexion exercise in the supine posture. Forty-four middle-aged individuals with T2D (14 women), and 35 healthy nondiabetic (ND) individuals (18 women) were tested. Leg blood flow (LBF) was measured between each contraction using venous occlusion plethysmography. During the incremental test peak force (Fpeak) relative to MVC was significantly reduced (P Ͻ 0.05) in men and women with T2D compared with their respective nondiabetic counterparts. Peak LBF and the slope of LBF relative to percentage F peak were also reduced (P Ͻ 0.05) in women with T2D compared with healthy women (peak blood flow, 460.6 Ϯ 126.8 vs. 628.3 Ϯ 347.7 ml/min; slope, 3.78 Ϯ 1.74 vs. 5.85 Ϯ 3.14 ml·min Ϫ1 · %Fpeak Ϫ1 ) and in men with T2D compared with nondiabetic men (peak blood flow, 621.7 Ϯ 241.3 vs. 721.2 Ϯ 359.7 ml/min; slope, 5.75 Ϯ 2.66 vs. 6.33 Ϯ 3.63 ml·min Ϫ1 ·%Fpeak Ϫ1 ). During constantload contractions at 30% MVC T2D did not affect the dynamic responses of LVC (LBF/MAP). However, at 70% MVC [completed by a subgroup of participants (20 with T2D, 6 women; 13 ND, 6 women)] the time constant of the second growth phase of LVC was longer and the amplitude of the first growth phase was lower (P Ͻ 0.05 for both) in men and women with T2D. The results suggest that the T2D-induced impairments in performance of the leg muscles are related to reductions in blood flow in both men and women. vascular conductance; blood flow; type 2 diabetes; muscle; exercise EXERCISE INTOLERANCE IS A major complication of type 2 diabetes (T2D) that is associated with worsening of cardiovascular outcomes and increased risk of mortality (45). Although the etiology of exercise intolerance in T2D is still not well understood, peak oxygen uptake (V O 2 ) responses to a graded exercise are reduced in men and women with T2D compared with nondiabetic healthy peers (16,19,25,34), and the rate of increase in V O 2 (V O 2 kinetics) is slowed in younger and middle-aged men and women with T2D (1,3,19,25,34) but not in older men with this disease (47). In healthy individuals, V O 2 kinetics during cycling exercise are limited by the muscle's oxidative capacity rather than O 2 delivery per se (30); however, it is likely that in patients with T2D, V O 2 kinetics are limited, at least in part, by reduced O 2 delivery to the contracting muscle.Support for reduced O 2 delivery as the source of the impairment in V O 2 control can be found in reports showing significantly slower heavy in...

BackgroundA number of dietary quality indices (DQIs) have been developed to assess the quality of dietary intake. Analysis of the intake of individual nutrients does not reflect the complexity of dietary behaviours and their association with health and disease. The aim of this study was to determine the dietary quality of individuals with type 2 diabetes mellitus (T2DM) using a variety of validated DQIs.MethodsIn this cross-sectional analysis of 111 Caucasian adults, 65 cases with T2DM were recruited from the Diabetes Day Care Services of St. Columcille’s and St. Vincent’s Hospitals, Dublin, Ireland. Forty-six controls did not have T2DM and were recruited from the general population. Data from 3-day estimated diet diaries were used to calculate 4 DQIs.ResultsParticipants with T2DM had a significantly lower score for consumption of a Mediterranean dietary pattern compared to the control group, measured using the Mediterranean Diet Score (Range 0–9) and the Alternate Mediterranean Diet Score (Range 0–9) (mean ± SD) (3.4 ± 1.3 vs 4.8 ± 1.8, P < 0.001 and 3.3 ± 1.5 vs 4.2 ± 1.8, P = 0.02 respectively). Participants with T2DM also had lower dietary quality than the control population as assessed by the Healthy Diet Indicator (Range 0–9) (T2DM; 2.6 ± 2.3, control; 3.3 ± 1.1, P = 0.001). No differences between the two groups were found when dietary quality was assessed using the Alternate Healthy Eating Index. Micronutrient intake was assessed using the Micronutrient Adequacy Score (Range 0–8) and participants with T2DM had a significantly lower score than the control group (T2DM; 1.6 ± 1.4, control; 2.3 ± 1.4, P = 0.009). When individual nutrient intakes were assessed, no significant differences were observed in macronutrient intake.ConclusionOverall, these findings demonstrate that T2DM was associated with a lower score when dietary quality was assessed using a number of validated indices.

We investigated if the magnitude of the Type 2 diabetes (T2D)-induced impairments in peak oxygen uptake (V̇O2) and V̇O2 kinetics was affected by menopausal status. Twenty-two women with T2D (8 premenopausal, 14 postmenopausal), and 22 nondiabetic (ND) women (11 premenopausal, 11 postmenopausal) matched by age (range = 30-59 yr) were recruited. Participants completed four bouts of constant-load cycling at 80% of their ventilatory threshold for the determination of V̇O2 kinetics. Cardiac output (CO) (inert gas rebreathing) was recorded at rest and at 30 s and 240 s during two additional bouts. Peak V̇O2 was significantly (P < 0.05) reduced in both groups with T2D compared with ND counterparts (premenopausal, 1.79 ± 0.16 vs. 1.55 ± 0.32 l/min; postmenopausal, 1.60 ± 0.30 vs. 1.45 ± 0.24 l/min). The time constant of phase II of the V̇O2 response was slowed (P < 0.05) in both groups with T2D compared with healthy counterparts (premenopausal, 29.1 ± 11.2 vs. 43.0 ± 12.2 s; postmenopausal, 33.0 ± 9.1 vs. 41.8 ± 17.7 s). At rest and during submaximal exercise absolute CO responses were lower, but the "gains" in CO larger (both P < 0.05) in both groups with T2D. Our results suggest that the magnitude of T2D-induced impairments in peak V̇O2 and V̇O2 kinetics is not affected by menopausal status in participants younger than 60 yr of age.