Leg Blood Flow and &amp;OV0312;O2 during Peak Cycle Exercise in Younger and Older Women

Proctor, David N.; Koch, Dennis W.; Newcomer, Sean C.; Le, Khoi U.; Smithmyer, Sandra L.; Leuenberger, Urs A.

doi:10.1249/01.mss.0000121951.10417.b5

Cited by 40 publications

(34 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although aged muscle may have a more enzymatic aerobic profile than younger adults, the blood flow at rest and during certain contractile conditions may be reduced with aging (Allman and Rice 2002). Additionally, muscle blood flow increases at a slower rate during heavy-resistance exercise in older adults compared to younger adults (Delorey et al 2005;Proctor et al 2004). Muscle fibers are organized into motor units; each motor unit includes one motoneuron and muscle fibers of the same type (Sargeant 1994).…”

Section: Muscle Structurementioning

confidence: 99%

An exploration of the association between frailty and muscle fatigue

Theou

Jones

Overend

et al. 2008

Appl. Physiol. Nutr. Metab.

View full text Add to dashboard Cite

Frailty is increasingly recognized as a geriatric syndrome that shares common biomedical determinants with rapid muscle fatigue: aging, disease, inflammation, physical inactivity, malnutrition, hormone deficiencies, subjective fatigue, and changes in neuromuscular function and structure. In addition, there is an established relationship between muscle fatigue and core elements of the cycle of frailty as proposed by Fried and colleagues (sarcopenia, neuroendocrine dysregulation and immunologic dysfunction, muscle weakness, subjective fatigue, reduced physical activity, low gait speed, and weight loss). These relationships suggest that frailty and muscle fatigue are closely related and that low tolerance for muscular work may be an indicator of frailty phenotype.

show abstract

Section: Muscle Structurementioning

confidence: 99%

An exploration of the association between frailty and muscle fatigue

Theou

Jones

Overend

et al. 2008

Appl. Physiol. Nutr. Metab.

View full text Add to dashboard Cite

show abstract

“…None of the subjects participated in moderate to high intensity aerobic exercise > 3 d•wk −1 or regular lower body resistance training > 2 d•wk −1 during the past 12 months. To objectively quantify aerobic fitness status, all of the subjects performed a continuous incremental leg cycle ergometer test (Lode) to maximal exertion to determine peak oxygen uptake (VO 2peak ), as described in detail previously [24].…”

Section: Subject Characteristicsmentioning

confidence: 99%

Hormone therapy is associated with preserved smooth muscle structure and dilation in the arterial vasculature of the leg in older women

2008

Self Cite

View full text Add to dashboard Cite

Long-term hormone therapy (HT) is associated with reduced intima-medial thickness (IMT), an established risk factor for atherosclerotic disease, in the femoral artery of healthy older women relative to age-matched non-hormone users. However, the influence of continuous, long-term HT on the relation between age, IMT, and smooth muscle dilation has not been investigated in the popliteal artery, an artery prone to stiffening and calcification. In the present study, popliteal artery IMT and smooth muscle dilation (the increase in diameter to sublingual nitroglycerin, NTG) were assessed with Doppler ultrasound in young (Y: n=16; age 23 ± 1 [mean ± S.E.M]), older non-HT (O non-HT: n=14; age 69 ± 1), and older HT (O HT: n=8; age 67 ± 1) healthy women. The ∼0.5mm increase in resting diameter observed in older non-HT women relative to young women was absent in older HT women, as was the age-related increase in IMT (Y: 0.52 ± 0.02 mm; O non-HT: 0.63 ± 0.02 mm; O HT: 0.56 ± 0.02 mm; p < 0.05 for age and hormone comparisons). NTG dilation (percent change above rest) was similarly attenuated in older non-HT women (Y: 8.6 ± 1 %; O non-HT: 3.0 ± 0.7 %; O HT: 7.4 ± 1.7 %; p < 0.05 for age and hormone comparisons), and NTG dilation was inversely related to IMT (p < 0.01). Collectively, these results suggest that long-term, continuous HT may alleviate the detrimental effects of aging on both structural changes and smooth muscle dilation of the popliteal artery in healthy women.

show abstract

“…However, recent experimental evidence regarding the maintenance or reduction in steady-state LBF and leg vascular conductance (LVC) in older adults is controversial (Proctor et al 1998a, b;Beere et al 1999;Proctor et al 2003a, b;Poole et al 2003;Lawrenson et al 2003;Proctor et al 2004). However, experimental models and exercise modes have limited comparisons between investigations.…”

Section: Introductionmentioning

confidence: 99%

Differences in exercise limb blood flow and muscle deoxygenation with age: contributions to O2 uptake kinetics

et al. 2010

View full text Add to dashboard Cite

The adjustments of pulmonary oxygen uptake V O2p limb blood flow (LBF) and muscle deoxygenation (ΔHHb) were examined during transitions to moderate-intensity, knee-extension exercise in seven older (OA; 71 ± 7 year) and seven young (YA; 26 ± 3 year) men. YA and OA performed repeated step transitions from an active baseline (3 W; 100 g) to a similar relative intensity of ~80% estimated lactate threshold (θ(L)), and YA also performed the same absolute work rate as the OA (24 W, 800 g). Breath-by-breath V O2p femoral artery LBF (Doppler ultrasound) and muscle HHb (near-infrared spectroscopy) were measured. Phase 2V O2p LBF, and ΔHHb data were fit with a mono-exponential model. τ V O2p was greater in OA (58 ± 21 s) than YA(80%) (31 ± 9 s) and YA(24W) (29 ± 11 s). The increase in LBF per increase in V O2p was not different between groups (5.3-5.8 L min(-1)/L min(-1)); however, the τLBF was greater in OA (44 ± 19 s) than YA(24W) (18 ± 7 s). The overall adjustment in ΔHHb (τ'ΔHHb) was not different between OA and YA, but was faster than τ V O2p in OA. This faster τ'ΔHHb than τ V O2p resulted in an "overshoot" of the normalized ΔHHb/Δ V O2p response relative to the steady state level that was significantly greater in OA compared with YA suggesting that the adjustment of microvascular blood flow is slowed in OA thereby requiring a greater reliance on O(2) extraction during the transition to exercise.

show abstract

Leg Blood Flow and &OV0312;O2 during Peak Cycle Exercise in Younger and Older Women

Cited by 40 publications

References 29 publications

An exploration of the association between frailty and muscle fatigue

An exploration of the association between frailty and muscle fatigue

Hormone therapy is associated with preserved smooth muscle structure and dilation in the arterial vasculature of the leg in older women

Differences in exercise limb blood flow and muscle deoxygenation with age: contributions to O2 uptake kinetics

Contact Info

Product

Resources

About