1 We have studied the effects of single oral doses of 80 mg propranolol and 100 mg metoprolol on the cardiovascular and respiratory responses to progressive exercise in nine healthy men in doubleblind, placebo-controlled experiment. As judged by their effects on exercise heart rate and cardiac output the doses of the two drugs used were equivalent.2 fp-adrenoceptor blockade reduced oxygen consumption by 3.5% over the whole work range with an increase in the respiratory exchange ratio of 0.056 units. Carbon dioxide production and exercise ventilation were unchanged. The two drugs had similar effects. Possible mechanisms for these observations are discussed.3 Perceived exertion during exercise was increased by both the f-adrenoceptor blocking drugs and this may be of relevance to the symptom of fatigue reported by patients on these drugs. Endurance, assessed as either total work done or maximal work achieved, was reduced by 15%.One of the main therapeutic uses of f-adrenergic receptor blocking drugs has been in the management of angina pectoris. Many authors have reported improved exercise tolerance in these patients with delayed onset of both ischaemic pain and ECG abnormalities and reduced dependence on coronary vasodilators- (Comerford & Besterman, 1976). 0-adrenoceptor blocking drugs are also widely used in the control of hypertension, often in patients whose exercise tolerance is presumably normal. As adrenergic mechanisms play a major role in facilitating oxygen transport through their involvement in the control of cardiovascular and respiratory adjustments during exercise, it is important to establish the effect of f-adrenoceptor blockade on exercise tolerance, particularly as there is now evidence that the cardiovascular reserves of untrained but otherwise healthy people are more limited than generaly appreciated (Wasserman, Whipp, Koyal & Beaver, 1973). Using normal individuals we have measured cardio-respiratory variables and the level ofperceived exertion during a standard progressive exercise test. Nine subjects were exercised to exhaustion while taking either metoprolol, propranolol or placebo. In this way the effects of both non-selective and more cardio-selective ,B-adrenergic receptor blockade have been studied. MethedsNine healthy adult male volunteers with normal lung function were used as subjects. They were aged 25 to 42 years (mean + s.d. 35 + 7 years), and gave their informed consent to a protocol which had been approved by the Ethical Committee of the Department of Physiology and Pharmacology.Identical tablets containing either 80 mg propranolol (Inderal, ICI) or 100 mg metoprolol (Betaloc, Astra) or lactose were used, and neither the subjects nor the experimenters were aware of the code used to identify the tablets. Three experiments were performed on each subject and at least 48 h elapsed between experiments on any individual. The order of the drugs was randomized between individuals to reduce bias due to any training effect of the procedure. Each experiment took 1.5 h and it started

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A small (28 g) mechanical accelerometer has been tested by subjecting it to controlled bench tests consisting of repetitive vertical oscillations on two designs of test rig. The accelerometer's 3-digit display provided a cumulated score with a maximum of 99.9 units. This score was compared with an independent count of the imposed oscillations and found to be linear with time (r = 0.996) and reproducible on retest (coefficient of variation = +/- 1.5%). The sensitivity ranged from 6.2 to 7.4 units/10,000 oscillations. The response was related to the maximal applied acceleration (calculated from the amplitude and frequency of the oscillations on the assumption that they were sinusoidal) and independent of the amplitude and frequency used. The threshold maximal acceleration was less than 2 m s-2 and the response had reached a plateau at 4 m s-2. During field studies the accelerometer was firmly attached over the hip in a waistband where it responded to the vertical accelerations produced by walking. When compared with an independent count of footsteps from a heel-mounted resistance pad the accelerometer score (after calibration) was not significantly different. The mean difference was (0.29 +/- 0.67, S.D.) 10(3) "steps" in a younger group (n = 8, mean age 39 years) and (0.46 +/- 1.08, S.D.) 10(3) "steps" in an older group of women (n = 6, mean age 65 years). Scores of around 10 X 10(3) "steps" can be expected in a day in moderately active young subjects and 40 X 10(3) "steps" in a week in the elderly. Simultaneously recorded scores from both right and left hips wee not significantly different.(ABSTRACT TRUNCATED AT 250 WORDS)

This paper describes a controlled study of the effects of an unsupervised walking-programme in 108 volunteers from among 580 middle-aged employees in a Nottingham light industrial company. Objective measurements of physical condition and of customary activity were made on four occasions at 12-week intervals. The subjects were randomly allocated to three groups and encouraged to follow a walking-programme in the first, second or third periods of the study: no activity was prescribed in the other periods. Compliance with the programme was estimated from log-cards and from a week's pedometer record. Although there were no significant differences between the changes seen in subjects following the walking-programme and those in control subjects, there were significant small improvements in physical condition and modest increases in customary activity in a) those subjects actually completing the programme, and b) the subjects measured before and after their programme, pooled without regard to the period of measurement. At least some of the increased activity is maintained for 12 weeks after the programme. The marginal changes suggest that the intensity of the training-programme as experienced by the subjects was close to the threshold for maintenance of physical condition in this age-group of workers.

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1. The effect on respiration of a single dose of propranolol has been studied in normal subjects. 2. The degree of beta-adrenoreceptor blockade was assessed in terms of the impaired heart-rate response to progressive exercise and the plasma propranolol concentration. 3. No effect of propranolol was demonstrated on either the ventilatory response to rebreathing CO2 in hyperoxia, or the response to progressive isocapnic hypoxia. Simple indices of maximal expiratory flow (FEV 1.0% and PEFR) were also unchanged. 4. The absence of any effect of propranolol on the chemical control of breathing in man is discussed in relation to the conflicting literature.

Salt taste detection thresholds have been measured by a forced-choice, up-down sip method in 146 healthy subjects aged 10-95 years, and in 43 ill elderly patients. Thresholds are shown to increase log linearly with age after the age of 20 years. Thresholds are higher in smokers than non-smokers and the lower thresholds of women are accounted for by their lower prevalence of smoking. Ill patients have higher thresholds than healthy subjects of the same age and this is not specifically associated with any diagnosis. The methodology of taste threshold measurement and earlier studies of taste thresholds are reviewed.