Muscle deoxygenation during ramp incremental cycle exercise in older adults with type 2 diabetes

PURPOSE: To explore profiles of fractional O 2 extraction (using near-infrared spectroscopy) during ramp incremental cycling in older individuals with type 2 diabetes (T2D). METHODS: Twelve individuals with T2D (mean ± SD, age: 63 ± 3 years) and 12 healthy controls (mean age: 65 ± 3 years) completed a ramp cycling exercise. Rates of muscle deoxygenation (i.e., deoxygenated haemoglobin and myoglobin, Δ[HHb + Mb]) profiles of the vastus lateralis muscle were normalised to 100% of the response, plotted against absolute (W) and relative (% peak) power output (PO) and fitted with a double linear regression model. RESULTS: Peak oxygen uptake (V̇O 2peak) was significantly (P &lt; 0.01) reduced in T2D (23.0 ± 4.2 ml.kg -1.min -1) compared with controls (28.3 ± 5.3 ml.kg -1.min -1). The slope of the first linear segment of the model was greater (median (interquartile range)) in T2D (1.06 (1.50)) than controls (0.79 (1.06)) when Δ%[HHb + Mb] was plotted as a function of PO. In addition, the onset of the second linear segment of the Δ%[HHb + Mb]/PO model occurred at a lower exercise intensity in T2D (101 ± 35 W) than controls (140 ± 34 W) and it displayed a near-plateau response in both groups. When the relationship of the Δ%[HHb + Mb] profile was expressed as a function of %PO no differences were observed in any parameters of the double linear model. CONCLUSIONS: These findings suggest that older individuals with uncomplicated T2D demonstrate greater fractional oxygen extraction for a given absolute PO compared with older controls. Thus, the reductions in V̇O 2peak in older people with T2D are likely influenced by impairments in microvascular O 2 delivery. </p

Time-course of V̇o₂ kinetics responses during moderate-intensity exercise subsequent to HIIT versus moderate-intensity continuous training in type 2 diabetes

We assessed the time-course of changes in oxygen uptake (V̇o2) and muscle deoxygenation (i.e., deoxygenated hemoglobin and myoglobin, [HHb + Mb]) kinetics during transitions to moderate-intensity cycling following 12 wk of low-volume high-intensity interval training (HIIT) vs. moderate-intensity continuous training (MICT) in adults with type 2 diabetes (T2D). Participants were randomly assigned to MICT ( n = 10, 50 min of moderate-intensity cycling), HIIT ( n = 9, 10 × 1 min at ∼90% maximal heart rate), or nonexercising control ( n = 9) groups. Exercising groups trained three times per week, and measurements were taken every 3 wk. [HHb + Mb] kinetics were measured by near-infrared spectroscopy at the vastus lateralis muscle. The local matching of O2 delivery to O2 utilization was assessed by the Δ[HHb + Mb]/ΔV̇o2 ratio. The pretraining time constant of the primary phase of V̇o2 (τV̇o2p) decreased ( P &lt; 0.05) at wk 3 of training in both MICT (from 44 ± 12 to 32 ± 5 s) and HIIT (from 42 ± 8 to 32 ± 4 s) with no further changes thereafter, whereas no changes were reported in controls. The pretraining overall dynamic response of muscle deoxygenation (τ'[HHb + Mb]) was faster than τV̇o2p in all groups, resulting in Δ[HHb + Mb]/V̇o2p showing a transient "overshoot" relative to the subsequent steady-state level. After 3 wk, the Δ[HHb + Mb]/V̇o2p overshoot was eliminated only in the training groups, so that τ'[HHb + Mb] was not different to τV̇o2p in MICT and HIIT. The enhanced V̇o2 kinetics response consequent to both MICT and HIIT in T2D was likely attributed to a training-induced improvement in matching of O2 delivery to utilization.NEW &amp; NOTEWORTHY High-intensity interval training and moderate-intensity continuous training elicited faster pulmonary oxygen uptake (V̇o2) kinetics during moderate-intensity cycling within 3 wk of training with no further changes thereafter in individuals with type 2 diabetes. These adaptations were accompanied by unaltered near-infrared spectroscopy-derived muscle deoxygenation (i.e. deoxygenated hemoglobin and myoglobin concentration, [HHb+Mb]) kinetics and transiently reduced Δ[HHb+Mb]-to-ΔV̇o2 ratio, suggesting an enhanced blood flow distribution within the active muscles subsequent to both training interventions. </p

Time course of changes in V̇o_2peak and O₂ extraction during ramp cycle exercise following HIIT versus moderate-intensity continuous training in type 2 diabetes

In the present study, we assessed the time course of adaptations in peak oxygen uptake (V̇o2peak) and muscle fractional oxygen (O2) extraction (using near-infrared spectroscopy) following 12 wk of low-volume high-intensity interval training (HIIT) versus moderate-intensity continuous endurance training (MICT) in adults with uncomplicated type 2 diabetes (T2D). Participants with T2D were randomly assigned to MICT (n = 12, 50 min of moderate-intensity cycling) or HIIT (n = 9, 10 × 1 min at ∼90% maximal heart rate) or to a nonexercising control group (n = 9). Exercising groups trained three times per week and measurements were taken every 3 wk. The rate of muscle deoxygenation (i.e., deoxygenated hemoglobin and myoglobin concentration, Δ[HHb + Mb]) profiles of the vastus lateralis muscle were normalized to 100% of the response, plotted against % power output (PO), and fitted with a double linear regression model. V̇o2peak increased (P &lt; 0.05) by week 3 of MICT (+17%) and HIIT (+8%), with no further significant changes thereafter. Total increases in V̇o2peak posttraining (P &lt; 0.05) were 27% and 14%, respectively. The %Δ[HHb + Mb] versus %PO slope of the first linear segment (slope1) was reduced (P &lt; 0.05) beyond 3 wk of HIIT and MICT, with no further significant changes thereafter. No changes in V̇o2peak or slope1 were observed in the control group. Low-volume HIIT and MICT induced improvements in V̇o2peak following a similar time course, and these improvements were likely, at least in part, due to an improved microvascular O2 delivery

Which patients received a ReSPECT form, what was documented and what were the patient outcomes? A protocol for a retrospective observational study investigating the impact of the COVID-19 pandemic on the implementation of the ReSPECT process

INTRODUCTION: Recommended Summary Plan for Emergency Care and Treatment (ReSPECT) is a UK advance care planning (ACP) initiative aiming to standardise the process of creating personalised recommendations for a person’s clinical care in a future emergency and therefore improve person-focused care. Implementation of the ReSPECT process across a large geographical area, involving both community and secondary care, has not previously been studied. In particular, it not known whether such implementation is associated with any change in outcomes for those patients with a ReSPECT form. Implementation of ReSPECT in the Bristol, North Somerset and South Gloucestershire (BNSSG) Clinical Commissioning Group (CCG) area overlapped with the first UK COVID-19 wave. It is unclear what impact the pandemic had on the implementation of ReSPECT and if this affected the type of patients who underwent the ReSPECT process, such as those with specific diagnoses or living in care homes. Patterns of clinical recommendations documented on ReSPECT forms during the first year of its implementation may also have changed, particularly with reference to the pandemic. To determine the equity and potential benefits of implementation of the ReSPECT form process in BNSSG and contribute to the ACP evidence base, this study will describe the characteristics of patients in the BNSSG area who had a completed ReSPECT form recorded in their primary care medical records before, during and after the first wave of the COVID-19 pandemic; describe the content of ReSPECT forms; and analyse outcomes for those patients who died with a ReSPECT form. METHODS AND ANALYSIS: We will perform an observational retrospective study on data, collected from October 2019 for 12 months. Data will be exported from the CCG Public Health Management data resource, a pseudonymised database linking data from organisations providing health and social care to people across BNSSG. Descriptive statistics of sociodemographic and health-related variables for those who completed the ReSPECT process with a clinician and had a documented ReSPECT form in their notes, in addition to their ReSPECT form responses, will be compared between before, during and after first COVID-19 wave groups. Additionally, routinely collected outcomes for patients who died in our study period will be compared between those who completed the ReSPECT process with a community clinician, hospital clinician or not at all. These include emergency department attendances, emergency hospital admissions, community nurse home visits, hospice referrals, anticipatory medication prescribing, place of death and if the patient died in preferred place of death. ETHICS AND DISSEMINATION: Approval has been obtained from a National Health Service Research Ethics Committee (20/YH/0185). Findings will be disseminated to policy decision-makers, care providers and the public through scientific meetings and peer-reviewed publication

Influence of type 2 diabetes on muscle deoxygenation during ramp incremental cycle exercise

We tested the hypothesis that type 2 diabetes (T2D) alters the profile of muscle fractional oxygen (O2) extraction (near-infrared spectroscopy) during incremental cycle exercise. Seventeen middle-aged individuals with uncomplicated T2D and 17 controls performed an upright ramp test to exhaustion. The rate of muscle deoxygenation (i.e. deoxygenated haemoglobin and myoglobin concentration, Δ[HHb+Mb]) profiles of the vastus lateralis muscle were normalised to 100% of the response, plotted against % power output (PO) and fitted with a double linear regression model. Peak oxygen uptake was significantly (P &lt; 0.05) reduced in individuals with T2D. The %Δ[HHb+Mb]/%PO slope of the first linear segment of the double linear regression function was significantly (P &lt; 0.05) steeper in T2D than controls (1.81±0.61 vs 1.35±0.43). Both groups displayed a near-plateau in Δ[HHb+Mb] at an exercise intensity (%PO) not different amongst them. Such findings suggest that a reduced O2 delivery to active muscles is an important underlying cause of exercise intolerance during a maximum graded test in middle-aged individuals with T2D.</p

Muscle deoxygenation during ramp incremental cycle exercise in older adults with type 2 diabetes

PURPOSE: To explore profiles of fractional O 2 extraction (using near-infrared spectroscopy) during ramp incremental cycling in older individuals with type 2 diabetes (T2D). METHODS: Twelve individuals with T2D (mean ± SD, age: 63 ± 3 years) and 12 healthy controls (mean age: 65 ± 3 years) completed a ramp cycling exercise. Rates of muscle deoxygenation (i.e., deoxygenated haemoglobin and myoglobin, Δ[HHb + Mb]) profiles of the vastus lateralis muscle were normalised to 100% of the response, plotted against absolute (W) and relative (% peak) power output (PO) and fitted with a double linear regression model. RESULTS: Peak oxygen uptake (V̇O 2peak) was significantly (P &lt; 0.01) reduced in T2D (23.0 ± 4.2 ml.kg -1.min -1) compared with controls (28.3 ± 5.3 ml.kg -1.min -1). The slope of the first linear segment of the model was greater (median (interquartile range)) in T2D (1.06 (1.50)) than controls (0.79 (1.06)) when Δ%[HHb + Mb] was plotted as a function of PO. In addition, the onset of the second linear segment of the Δ%[HHb + Mb]/PO model occurred at a lower exercise intensity in T2D (101 ± 35 W) than controls (140 ± 34 W) and it displayed a near-plateau response in both groups. When the relationship of the Δ%[HHb + Mb] profile was expressed as a function of %PO no differences were observed in any parameters of the double linear model. CONCLUSIONS: These findings suggest that older individuals with uncomplicated T2D demonstrate greater fractional oxygen extraction for a given absolute PO compared with older controls. Thus, the reductions in V̇O 2peak in older people with T2D are likely influenced by impairments in microvascular O 2 delivery. </p

Low-volume HIIT and MICT speed V̇o₂ kinetics during high-intensity “work-to-work” cycling with a similar time-course in type 2 diabetes

We assessed the rates of adjustment in oxygen uptake (V̇O2) and muscle deoxygenation [i.e., deoxygenated hemoglobin and myoglobin, (HHb + Mb)] during the on-transition to high-intensity cycling initiated from an elevated baseline (work-to-work, w-to-w) before training and at weeks 3, 6, 9, and 12 of low-volume high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) in type 2 diabetes (T2D). Participants were randomly assigned to MICT (n = 11, 50 min of moderate-intensity cycling), HIIT (n = 8, 10 × 1 min of high-intensity cycling separated by 1 min of light cycling) or nonexercising control (n = 9) groups. Exercising groups trained three times per week. Participants completed two w-to-w transitions at each time point consisting of sequential step increments to moderate- and high-intensity work-rates. [HHb + Mb] kinetics were measured by near-infrared spectroscopy at the vastus lateralis muscle. The pretraining time constant of the primary phase of V̇O2 (V̇O2 τp) and the amplitude of the V̇O2 slow component (V̇O2  As) of the high-intensity w-to-w bout decreased (P &lt; 0.05) by a similar magnitude at week 3 of training in both MICT (from 56 ± 9 to 43 ± 6 s, and from 0.17 ± 0.07 to 0.09 ± 0.05 L/min, respectively) and HIIT (from 56 ± 8 to 42 ± 6 s, and from 0.18 ± 0.05 to 0.09 ± 0.08 L/min, respectively) with no further changes thereafter. No changes were reported in controls. The parameter estimates of Δ[HHb + Mb] remained unchanged in all groups. MICT and HIIT elicited comparable improvements in V̇O2 kinetics without changes in muscle deoxygenation kinetics during high-intensity exercise initiated from an elevated baseline in T2D despite training volume and time commitment being ∼50% lower in the HIIT group.NEW &amp; NOTEWORTHY Three weeks of high-intensity interval training and moderate-intensity continuous training decreased the time constant of the primary phase of oxygen uptake (V̇O2) and amplitude of the V̇O2 slow component during a high-intensity exercise initiated from an elevated baseline, a protocol that mimics the abrupt metabolic transitions akin to those in daily life, in type 2 diabetes. These V̇O2 kinetics improvements were maintained until the end of the 12-wk intervention without changes in muscle deoxygenation kinetics

Low-volume HIIT and MICT speed V̇O₂ kinetics during high-intensity "work-to-work" cycling with a similar time-course in type 2 diabetes

We assessed the rates of adjustment in oxygen uptake (V̇o2) and muscle deoxygenation [i.e., deoxygenated hemoglobin and myoglobin, (HHb + Mb)] during the on-transition to high-intensity cycling initiated from an elevated baseline (work-to-work, w-to-w) before training and at weeks 3, 6, 9, and 12 of low-volume high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) in type 2 diabetes (T2D). Participants were randomly assigned to MICT ( n = 11, 50 min of moderate-intensity cycling), HIIT ( n = 8, 10 × 1 min of high-intensity cycling separated by 1 min of light cycling) or nonexercising control ( n = 9) groups. Exercising groups trained three times per week. Participants completed two w-to-w transitions at each time point consisting of sequential step increments to moderate- and high-intensity work-rates. [HHb + Mb] kinetics were measured by near-infrared spectroscopy at the vastus lateralis muscle. The pretraining time constant of the primary phase of V̇o2 (V̇o2 τp) and the amplitude of the V̇o2 slow component (V̇o2 As) of the high-intensity w-to-w bout decreased ( P &lt; 0.05) by a similar magnitude at week 3 of training in both MICT (from 56 ± 9 to 43 ± 6 s, and from 0.17 ± 0.07 to 0.09 ± 0.05 L/min, respectively) and HIIT (from 56 ± 8 to 42 ± 6 s, and from 0.18 ± 0.05 to 0.09 ± 0.08 L/min, respectively) with no further changes thereafter. No changes were reported in controls. The parameter estimates of Δ[HHb + Mb] remained unchanged in all groups. MICT and HIIT elicited comparable improvements in V̇o2 kinetics without changes in muscle deoxygenation kinetics during high-intensity exercise initiated from an elevated baseline in T2D despite training volume and time commitment being ∼50% lower in the HIIT group. NEW &amp; NOTEWORTHY Three weeks of high-intensity interval training and moderate-intensity continuous training decreased the time constant of the primary phase of oxygen uptake (V̇o2) and amplitude of the V̇o2 slow component during a high-intensity exercise initiated from an elevated baseline, a protocol that mimics the abrupt metabolic transitions akin to those in daily life, in type 2 diabetes. These V̇o2 kinetics improvements were maintained until the end of the 12-wk intervention without changes in muscle deoxygenation kinetics. </p