Effects of menthol application on the skin during prolonged immersion in cool and cold water.

The aim of the study was to compare the effect of skin surface menthol application on rectal temperature (Tre) during prolonged immersion in cool and cold water. We hypothesized that menthol application would lead to a slower Tre decline due to the reduced heat loss as a consequence of the menthol-induced vasoconstriction and that this effect would be attenuated during cold-water immersion. Six male subjects were immersed for 55 minutes in stirred cool (24°C) or cold (14°C) water immediately after attaining a Tre of 38°C by cycling at 60% of maximum heart rate on two occasions: without (ΝM) and with (M) whole-body skin application of menthol cream. Tre, the proximal-distal skin temperature gradient, and oxygen uptake were continuously measured. ANOVA with repeated measures was employed to detect differences among variables. Significance level was set at 0.05. The area under the curve for Tre was calculated and was greater in 24°C M (-1.81 ± 8.22 a.u) compared to 24°C NM (-27.09 ± 19.09 a.u., P = .03, r = .90), 14°C NM (-18.08 ± 10.85 a.u., P = .03, r = .90), and 14°C M (-11.71 ± 12.58 a.u, P = .05, r = .81). In cool water, oxygen uptake and local vasoconstriction were increased (P ≤ .05) by 39 ± 25% and 56 ± 37%, respectively, with menthol compared to ΝM, while no differences were observed in cold water. Menthol application on the skin before prolonged immersion reduces heat loss resulting in a blunted Tre decline. However, such a response is less obvious at 14°C water immersion, possibly because high-threshold cold-sensitive fibers are already maximally recruited and the majority of cold receptors saturated.

Effects of menthol application on the skin during prolonged immersion in swimmers and controls.

We hypothesized that menthol application on the skin would enhance vasoconstriction of subjects immersed in cool water, which would reduce heat loss and rectal temperature (Tre) cooling rate. Furthermore, it was hypothesized that this effect would be greater in individuals acclimatized to immersion in 24 °C water, such as swimmers. Seven swimmers (SW) and seven physical education students (CON) cycled at 60% VO2 max until Tre attained 38 °C, and were then immediately immersed in stirred water maintained at 24 °C on two occasions: without (NM) and with (M; 4.6 g per 100 mL of water) whole-body skin application of menthol cream. Heart rate, Tre, proximal-distal skin temperature gradient, oxygen uptake (VO2 ), electromyographic activity (EMG), and thermal sensation were measured. Tre reduction was similar among SW and CON in NM and CON in M (-0.71±0.31 °C in average), while it was smaller for SW in M (-0.37±0.18 °C, P < 0.01). VO2 and heart rate were greater in M compared with NM condition (P = 0.01). SW in M exhibited a shift of the threshold for shivering, as reflected in increased VO2 and EMG activity, toward a higher Tre compared with the other trials. Menthol application on the skin before immersion reduces heat loss, but defends Tre decline more effectively in swimmers than in non-swimmers.

High intensity, interval exercise improves quality of life of patients with chronic heart failure: a randomized controlled trial.

BACKGROUND: The aim of this study was to evaluate the effect of high intensity, interval exercise on quality of life (QoL) and depression status, in chronic heart failure (CHF) patients. METHODS: A randomized controlled trial (phase III). Of the 100 consecutive CHF patients (NYHA classes II-IV, ejection fraction ≤ 50%) that were randomly allocated to exercise intervention (n = 50, high-intensity intermittent endurance training 30 s at 100% of max workload, 30 s at rest, for 45 min/day-by-12 weeks) or no exercise advice (n = 50), 72 (exercise group, n = 33, 63 ± 9 years, 88% men, 70% ischemic CHF and control group, n = 39, 56 ± 11 years, 82% men, 70% ischemic CHF) completed the study. QoL was assessed using the validated and translated Minnesota Living with Heart Failure questionnaire. Depressive symptomatology was evaluated using the validated and translated Zung Depression Rating Scale (ZDRS). Maximal oxygen uptake (VO(2max)) and carbon dioxide production (VCO(2max)) were also measured breath-by-breath. RESULTS: Data analysis demonstrated that in the intervention group MLHFQ score was reduced by 66% (P = 0.003); 6-min-walk distance increased by 13% (P < 0.05), VO(2max) level increased by 31% (P = 0.001), VCO(2max) level increased by 28% (P = 0.001) and peak power output increased by 25% (P = 0.001), as compared with the control group. CONCLUSION: High intensity, systematic aerobic training, could be strongly encouraged in CHF patients, since it improves QoL, by favorably modifying their fitness level.

On- and off-exercise kinetics of cardiac output in response to cycling and walking in COPD patients with GOLD Stages I-IV.

Exercise-induced dynamic hyperinflation and large intrathoracic pressure swings may compromise the normal increase in cardiac output (Q) in Chronic Obstructive Pulmonary Disease (COPD). Therefore, it is anticipated that the greater the disease severity, the greater would be the impairment in cardiac output during exercise. Eighty COPD patients (20 at each GOLD Stage) and 10 healthy age-matched individuals undertook a constant-load test on a cycle-ergometer (75% WR(peak)) and a 6min walking test (6MWT). Cardiac output was measured by bioimpedance (PhysioFlow, Enduro) to determine the mean response time at the onset of exercise (MRTon) and during recovery (MRToff). Whilst cardiac output mean response time was not different between the two exercise protocols, MRT responses during cycling were slower in GOLD Stages III and IV compared to Stages I and II (MRTon: Stage I: 45±2, Stage II: 65±3, Stage III: 90±3, Stage IV: 106±3s; MRToff: Stage I: 42±2, Stage II: 68±3, Stage III: 87±3, Stage IV: 104±3s, respectively). In conclusion, the more advanced the disease severity the more impaired is the hemodynamic response to constant-load exercise and the 6MWT, possibly reflecting greater cardiovascular impairment and/or greater physical deconditioning.