Cardiopulmonary response to exercise in COPD and overweight patients: relationship between unloaded cycling and maximal oxygen uptake profiles.

Cardiopulmonary response to unloaded cycling may be related to higher workloads. This was assessed in male subjects: 18 healthy sedentary subjects (controls), 14 hypoxemic patients with chronic obstructive pulmonary disease (COPD), and 31 overweight individuals (twelve were hypoxemic). They underwent an incremental exercise up to the maximal oxygen uptake (VO2max), preceded by a 2 min unloaded cycling period. Oxygen uptake (VO2), heart rate (HR), minute ventilation (VE), and respiratory frequency (fR) were averaged every 10 s. At the end of unloaded cycling period, HR increase was significantly accentuated in COPD and hypoxemic overweight subjects (resp., +14 ± 2 and +13 ± 1.5 min(-1), compared to +7.5 ± 1.5 min(-1) in normoxemic overweight subjects and +8 ± 1.8 min(-1) in controls). The fR increase was accentuated in all overweight subjects (hypoxemic: +4.5 ± 0.8; normoxemic: +3.9 ± 0.7 min(-1)) compared to controls (+2.5 ± 0.8 min(-1)) and COPDs (+2.0 ± 0.7 min(-1)). The plateau VE increase during unloaded cycling was positively correlated with VE values measured at the ventilatory threshold and VO2max. Measurement of ventilation during unloaded cycling may serve to predict the ventilatory performance of COPD patients and overweight subjects during an exercise rehabilitation program.

Effects of hydration and water deprivation on blood viscosity during a soccer game in sickle cell trait carriers.

The present study compared the changes in blood viscosity, hydration status, body temperature and heart rate between a group of sickle cell trait (SCT) carriers and a control (Cont) group before and after a soccer game performed in two conditions: one with water offered ad libitum (hydration condition; Hyd) and the other one without water (dehydration condition; Dehyd). Blood viscosity and haematocrit per blood viscosity ratio (HVR; an index of red blood cell oxygen transport effectiveness) were measured before and at the end of each game. Resting blood viscosity was greater in the SCT carriers than in the Cont group. The increase of blood viscosity over baseline at the end of the game in the Cont group was similar in the two conditions. In contrast, the change in blood viscosity occurring in SCT carriers during soccer games was dependant on the experimental condition: (1) in Dehyd condition, blood viscosity rose over baseline; (2) in Hyd condition, blood viscosity decreased below resting level reaching Cont values. The Cont group had higher HVR than SCT carriers at rest. HVR remained unchanged in the Cont group at the end of the games, whatever the experimental condition. Although HVR of SCT carriers decreased below baseline at the end of the game performed in Dehyd condition, it increased over resting level in Hyd condition reaching the values of the Cont group. Our study demonstrated that ad libitum hydration in exercising SCT carriers normalises the blood hyperviscosity.

Calf muscle stimulation with the Veinoplus device results in a significant increase in lower limb inflow without generating limb ischemia or pain in patients with peripheral artery disease.

OBJECTIVE: Increase in arterial inflow to the lower limbs is important to obtain functional improvement in peripheral artery disease (PAD) patients with claudication. The aim of this study was to assess the effect of electrical stimulation of calf muscles on arterial inflow and tissue oxygen content in PAD in the area of stimulation. METHODS: Fifteen adult patients [mean (standard deviation) age, 62 (12 ) years; height, 165 (8)cm; weight, 76 (13) kg; lowest ankle-brachial index 0.66 (0.19)] with stable arterial claudication were recruited. All patients performed a treadmill test (3.2 km/h, 10% slope) associated with a transcutaneous oximetry test expressed as decrease from rest of oxygen pressure (DROP) index values (calf changes minus chest changes from rest) with a maximum walking distance (median [25th/75th percentiles]) of 295 [133-881] m. The DROP index on the symptomatic side was -25 [-18/-34] mm Hg. On another day the patients underwent electrical stimulation in the seated position on the leg that was the most symptomatic on the treadmill. After resting values were recorded, the gastrocnemius was stimulated for 20minutes at increasing contraction rates at 5-minute steps of 60, 75, 86, and 100bpm on the most symptomatic side. Arterial blood inflow with duplex Doppler ultrasound scanning of the femoral artery, DROP transcutaneous oxygen pressure value, and oxygen concentration (O2Hb) from the near-infrared spectroscopic signal of the calf were recorded on both sides. Patients were instructed to report eventual contraction-induced pain in the stimulated calf. Results are given as mean (standard deviation) or median [25th/75th percentiles] according to distribution, and the level of statistical significance was set at P < .05 on two-tailed tests. RESULTS: Lower limb inflow (mL/min) was 64 [48/86] vs 63 [57/81] (P> .05) before stimulation, 123 [75/156] vs 57 [44/92] (P < .01) at 60bpm, 127 [91/207] vs 49 [43/68] (P < .01) at 75bpm, 140 [84/200] vs 57 [45/71] (P < .01) at 86bpm, and 154 [86/185] vs 55 [46/94] (P < .01) at 100bpm on the stimulated vs nonstimulated limb, respectively. No apparent decrease or significant leg difference was observed in DROP index or O2Hb values. None of the patients reported contraction-induced pain in the leg. CONCLUSIONS: Electrical stimulation of calf muscle with the Veinoplus device results in a significant increase of arterial inflow without measurable muscle ischemia or pain. Potential use of this device as an adjuvant treatment to improve walking capacity in PAD patients remains to be evaluated.

Effects of hydration and dehydration on blood rheology in sickle cell trait carriers during exercise.

This study compared the hemorheological responses of a group of sickle cell trait (SCT) carriers with those of a control (Cont) group in response to 40 min of submaximal exercise (exercise intensity, 55% aerobic peak power) performed in two conditions: one with water offered ad libitum, i.e., the hydration (Hyd) condition, and one without water, i.e., the dehydration (Dehyd) condition. Blood and plasma viscosities, as well as red blood cell rigidity, were determined at rest, at the end of exercise, and at 2 h recovery with a cone plate viscometer at high shear rate and 37 degrees C. The SCT and Cont groups lost 1 +/- 0.7 and 1.6 +/- 0.6 kg of body weight, respectively, in the Dehyd condition, indicating a significant effect of water deprivation compared with the Hyd condition, in which body weight remained unchanged. Plasma viscosity increased with exercise and returned to baseline during recovery independently of the group and condition. As previously demonstrated, resting blood viscosity was greater in the SCT carriers than in the Cont group. Blood viscosity increased by the end of exercise and returned to baseline at 2 h recovery in the Cont group in both conditions. The blood viscosity of SCT carriers did not change in response to exercise in the Dehyd condition and remained elevated at 2 h recovery. This extended hyperviscosity, in association with other biological changes induced by exercise, could be considered as a risk factor for exercise-related events in SCT carriers, similar to vasoocclusive crises, notably during the recovery. In contrast, the Hyd condition normalized the hyperviscosity and red blood cell rigidity of the SCT carriers, with blood viscosity values reaching the same lower values as those found in the Cont group during the recovery. Adequate hydration of SCT carriers should be strongly promoted to reduce the clinical risk associated with potential hyperviscosity complications.

[Doctors belonging to the Senegalese Association of Sport Medicine and doping in sports: survey on knowledge and attitudes]. / Médecins de l'Association sénégalaise de médecine du sport et dopage sportif: enquête sur les connaissances et attitudes.

Doping in sports is as old as sports, but it grew considerably during the 20th century with the arrival in stadiums during the 1990s of amphetamines and anabolic steroids as well as such peptide hormones as erythropoietin. The international fight against doping took a giant step forward in 1999 with the creation of the world antidoping agency (WADA). This study is part of that fight. It follows an earlier survey of retail pharmacists in Senegal and aims to evaluate the knowledge about doping of doctors belonging to the Senegalese Association of Sports Medicine and to assess their attitude towards this phenomenon. Its goal is to determine how best to involve them in preventive actions. We conducted a survey in 2001 and randomly selected and interviewed 60 of the 92 doctors in the association. The questionnaire focused on three areas: their knowledge of doping, their attitudes to it, and the means of prevention that they proposed. The results showed that only 11 of the 60 doctors knew the definition of doping and 15% of doctors could not cite any family of doping products. They were aware mainly of testosterone and other anabolic steroids (84.3%), then amphetamines and other stimulants (64.7%), and finally peptide hormones (58.8%). The subjects mentioned blood doping and pharmacological manipulations as forbidden methods. They considered that the four groups of drugs most often used by athletes for doping were, in descending order, anabolic steroids, stimulants, peptide hormones and corticoids. Eighty per cent of doctors think that Senegalese athletes use doping products and that the sports most involved are football, wrestling, track and field and basketball. They also think that doping is a form of drug addiction and a public health problem. Eleven doctors (18%) said they had been contacted for information on use of doping products. The interviewees consider that the three best methods of prevention include information about side effects, unannounced urine and blood tests, and sanctions. This work shows that Senegalese athletes may use doping; it contains no direct proofs but many indirect indicators. Success against doping requires preventive activities that should be conducted jointly for trainers, sports federations and doctors of the Senegalese Association of Sports Medicine and then by all of them for athletes, who are the primary targets of any prevention campaign.