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Biomedical subjects

M Burtscher

Publications and source records attributed to M Burtscher.

16 recordsLinked to original sources
PubMed2001

Cardiopulmonary and metabolic responses in healthy elderly humans during a 1-week hiking programme at high altitude.

Worldwide there are approximately 100 million visitors to high altitude annually and about 15% of those are elderly. Nevertheless, basic information on the cardiopulmonary and metabolic responses to physical activity at high altitude in the elderly is scarce. Therefore, we studied 20 voluntary healthy elderly subjects (55-77 years) who were randomly assigned to a low- (600 m) or a high altitude (2,000 m) group. Both groups increased the duration of their daily hiking from 2.5 to 5 h during a period of 1 week. Pre- and post-hiking cardiopulmonary variables at rest were measured daily. Exercise tests (3 min step test) were performed on days 1, 4 and 7. Of the morning values at rest, only arterial oxygen saturation (SaO2) had decreased after the 1st night at high altitude. After hiking however, SaO2 was diminished on all days at high altitude. Post-hiking heart rates increased from baseline on days 1 and 2 in the low- and on days 1-5 in the high-altitude group. Exercising SaO2 (%) in the three tests was decreased [84.9 (SD 2.8), 88.1 (SD 2.1), 87.2 (SD 2.3)] compared to baseline [93.2 (SD 2.0); P < 0.05] and blood lactate concentrations were increased [3.1 (SD 0.7), 3.4 (SD 0.3), 3.3 (SD 0.2)] compared to baseline [2.7 (SD 0.6); P < 0.05] in all tests at high altitude. The 1-week hiking programme was well tolerated by the healthy elderly at both low and high altitudes. Ventilatory adaptation to high altitude in the elderly seemed to have been completed within the first 2 days during the measurements at rest. However, cardiopulmonary and metabolic responses to exercise were increased and recovery from exercise was delayed during the 1-week hiking programme at high altitude. Heart rate and SaO2 measurements are considered to be highly sensitive in estimating the state of acclimatisation and for monitoring exercise intensity and duration at high altitude.

Aged↗
PubMed2001

Effects of aspirin during exercise on the incidence of high-altitude headache: a randomized, double-blind, placebo-controlled trial.

OBJECTIVE: To evaluate the efficacy of aspirin for headache when exercising during acute high-altitude exposure. BACKGROUND: Aspirin effectively prevents headache when mostly resting during acute high-altitude exposure. However, the majority of individuals exposed to high altitude perform mountaineering activities, which might trigger headache. DESIGN: Randomized, double-blind, placebo-controlled trial. METHODS: Thirty-one healthy volunteers (20 men, 11 women; aged 22 to 59 years) were transported to an altitude of about 3000 meters and climbed up to 3800 meters. They then descended to a mountain hut at 3480 meters and spent 2 nights there. Tablets (placebo or 320 mg aspirin) were administered three times at 4-hour intervals, beginning 2 hours before arrival at high altitude. Headache scoring and measurements of heart rate, blood pressure, and arterial oxygen saturation were performed. RESULTS: Ninety-three percent (14 of 15) of the placebo group and 56% (9 of 16) of the aspirin group developed headache when mountaineering activities were performed during acute exposure to high altitude (P<.05). Five hours after arrival at high altitude, mean resting oxygen saturation was 86.1% +/- 2.1% with aspirin and 85.7 % +/- 2.8% with placebo (P =.66). However, subjects in the aspirin group developed headache at saturation values less than or equal to 86%, while those in the placebo group developed headache at saturation values less than 90%. CONCLUSIONS: Although the prophylactic intake of about 1 gram of aspirin reduced the headache incidence when exercising during acute high-altitude exposure, the incidence of headache was higher than previously shown for resting conditions. Aspirin resulted in tolerance to lower arterial oxygen saturation without development of headache; exercise had the opposite effect.

Acute Disease↗
PubMed2000

Prior myocardial infarction is the major risk factor associated with sudden cardiac death during downhill skiing.

More than 90% of all sudden cardiac deaths (SCDs) during downhill skiing, the most popular winter sport world-wide, are attributed to men over the age of 34. However, no data exist on additional risk factors and triggers for SCD related to downhill skiing. Therefore risk factor profiles of 68 males who died from SCD during downhill skiing were compared to those of 204 matched controls. Skiers who suffered SCD had much more frequently prior myocardial infarction (MI) (41% vs. 1.5%; p<0.001), hypertension (50% vs. 17%; p<0.001), known coronary heart disease (CHD) without prior MI (9% vs. 3%; p=0.05) and were less engaged in strenuous exercise (4% vs. 15%; p<0.05) when compared to controls. Multivariate analyses even enhanced the importance of these risk factors. Downhill skiing is considered to be a serious trigger for SCD especially in skiers with prior MI but also for those with hypertension, known CHD without prior MI, or insufficient adaptation to strenuous exercise. Skiing-related increased sympathetic activity might well disturb the autonomic balance with subsequent arrhythmias and/or may increase cardiac work and platelet aggregability with possible plaque rupture and coronary thrombosis. Therefore adaptation to high intensity exercise and therapeutic interventions or abstinence from skiing in certain cases should be considered for downhill skiers at high risk.

Aged↗
PubMed1999

[High altitude headache: epidemiology, pathophysiology, therapy and prophylaxis].

Headache is known to be the predominant symptom in acute mountain sickness which is also frequently accompanied by nausea, vomiting and insomnia. Nowadays, every year millions of skiers and mountaineers are attracted to mountains all over the world. At altitudes between 2500 m and 5000 m about 20% to 90% of those who are not adapted to high altitude will experience high altitude headache (HAH). It is well documented that HAH can be best prevented by observance of the golden rule: not to go too high too fast. Although many mountaineers are aware of this rule, its observance is complicated by unknown individual susceptibility, the location of mountain huts, the use of cable cars, limited holiday time, unfavorable weather or avalanche conditions. Therefore, there is a widespread use of drugs for the treatment and prevention of HAH. In the past, the increase in cerebral blood flow during acute hypoxia was thought to be the main cause of HAH. More recent findings, however, have caused this hypothesis to be reduced in importance and have supported the pathogenetic consequence of sensitization of intracranial pain-sensitive structures. The effectiveness of cyclooxygenase inhibition for the treatment and prevention of HAH suggests that especially prostaglandins may be an important mediator between hypoxia and HAH. Besides oxygen, acetazolamide, dexamethasone and especially inhibitors of prostaglandin synthesis such as ibuprofen and naproxen are approved for the treatment of HAH. Acetazolamide, dexamethasone, and aspirin were also found to prevent HAH. The most beneficial effects however, may be achieved by the combined application of acetazolamide and aspirin. This combination increases oxygenation and reduces prostaglandin synthesis.

Acute Disease↗
PubMed1997

[The preemptive action of ketoprofen. Randomized, double-blind study with gynecologic operations].

STUDY OBJECTIVE: Ketoprofen exerts its clinical effect by inhibition of prostaglandin synthesis, but also acts as an NMDA-receptor antagonist by means of the kynurenic acid. Based on ketoprofen's supposed central mechanism of analgesia, we expected a preemptive effect, which was assessed by the present study. METHODS: In a prospective, randomised, double-blind investigation of 48 patients undergoing gynaecological procedures (laparotomy, pelvioscopy), the first group received ketoprofen 2 mg/kg body weight i.v. 20 min before the beginning of surgery and placebo i.v. at the end of surgery. In the second group, placebo was administered first and ketoprofen at the end of surgery. Premedication and anaesthesia were standardised by protocol. The postoperative analgesic patient-controlled analgesia consumption by was also standardised (piritramide). Efficacy was assessed by visual analogue scale (VAS) and total requirement of analgesics within the first 24 postoperative hours. The time to the first request for postoperative analgesics was also recorded. Safety was assessed by continuous monitoring of vital parameters such as respiratory rate, heart rate, blood pressure, and oxygen saturation. The incidence and severity of adverse events was documented. RESULTS: There were no significant differences between the groups in demographic data or type or duration of surgery. The time to the first request for analgesic, VAS pain intensity, and analgesic consumption in the first 24 h post-surgery were not significantly different between the groups (t-test). CONCLUSION: Ketoprofen is an effective post-operative analgesic in combination with an opioid, but has no preemptive effect according to the results of this study.

Adolescent↗
PubMed1996

Benefits of training at moderate altitude versus sea level training in amateur runners.

After more than 25 years of research of altitude training (AT) there is no consensus regarding either the training programme at altitude or the effects of AT on performance at sea level. Based on a review of the research work on AT, we investigated combined base training and interval training at moderate altitude and compared immediate and delayed effects on sea level performance with those following similar sea level training (SLT). The altitude group (AG, 10 male amateur runners) trained at 2315 m (natural altitude) and the sea level group (SLG, 12 male amateur runners) at 187 m. Both groups performed 7 days of base training (running on a trail) lasting between 60 and 90 min a day and 5 days of interval training (speed and hill runs) for between 10 and 45 min a day. Incremental exercise tests were performed 1 week before (t1), 3 days after (t2) and 16 days after (t3) the 12-day main training period. Within AG, exercise performance improved from t1 to t2 by 8% (P < 0.05) and from t2 to t3 by 8% (P < 0.05). Maximum oxygen uptake (VO2max) increased from t2 to t3 by 10% (P < 0.05). Within SLG exercise performance increased from t2 to t3 by 8% (P < 0.05). At t3, relative and absolute VO2max in AG were significantly higher in comparison with SLG (P = 0.005 and P = 0.046 respectively). The improved performance 3 days after AT may be explained in part by an increased oxygen uptake at submaximal exercise intensities without a change in VO2max. Further enhancement in performance 2 weeks after AT, however, seems to have been due to the clearly enhanced VO2max. Progressive cardiovascular adjustments might have contributed primarily to the time-dependent improvements observed after AT, possibly by an enhanced stroke volume overcompensating the reduced heart rates during submaximal exercise. In conclusion, our findings would suggest that training at a moderate natural altitude improves performance at sea level more than SLT. Combining base and interval training with regulation of intensity by training at constant heart rates during acclimatization at altitude would seem to be a successful training regimen for amateur runners. Most beneficial effects became apparent during the subsequent SLT around 2 weeks after return from altitude. Therefore, we are convinced that AT should be reconsidered as a potent tool for enhancing aerobic capacity, at least in non-elite athletes.

Adult↗
PubMed1994

Motor symptoms similar to parkinsonism in heavy smokers.

The major objective in this study was a comparison of the motor performance of young male smokers and non-smokers. We tested the endurance capacity, maximal isometric strength, speed of whole-body movements, flexibility and balancing ability of 74 smokers and 118 non-smokers. Then we measured the balancing ability, the visual reaction time and the speed of limb movements of non-smokers and heavy smokers depending on the time of abstinence from smoking. The balancing ability of heavy smokers deteriorates in comparison with non-smokers after an abstinence period of 11-120 min by 42% (p < 0.05), and after more than 120 min by 51% (p < 0.01). Heavy smokers had a longer reaction time both after 2 hours of abstinence and after smoking. The speed of limb movements is decreased after not smoking for a brief period compared to non-smokers and clearly improved immediately after smoking. This deterioration of motor performance of heavy smokers after a short period of abstinence appears similar to the motor symptoms of Parkinsonism and is "treated" by cigarette smoking.

Adolescent↗