Björn Ahlborg

Prevalence of migraine and cluster headache in Swedish men of 18.

SYNOPSIS

Physical characteristics and allergic history in young men with migraine and other headaches.

SYNOPSIS

Influence of Vibration on Work Performance during Ergometer Cycling

With a view to investigating how vibration affects dynamic working capacity, exercise tests were performed both with and without superimposed vibration. The performance of 8 healthy, non-smoking 20-year-old males exercising on a cycle ergometer at a constant load was studied on four occasions, with and without vibration in a randomly chosen order. The frequency of the vibration, which was applied vertically through the pedals, was 20 Hz and the acceleration was 20 m/s2 RMS. The handlebars and saddle of the cycle were insulated from the vibration. The exercise time averaged 47 min with vibration and 60 min without. The vibratory stress reduced the exercise time by 13 +/- 2.9 min (mean +/- SEM) (P less than 0.005). The average heart rate when the exercise was stopped was 180.3 beats/min with vibration and 180.7 beats/min without. The systolic blood pressure after 20 min averaged 188 mm Hg with vibration and 187 mm Hg without vibration. Both with and without vibration, 6 of the 8 subjects stated that leg fatigue was the cause of their inability to continue pedalling longer. Our conclusion is that in the performance of dynamic muscular work endurance may decrease under the influence of vibration.

Significance of Primary T Wave Aberrations in the Electrocardiogram of Asymptomatic Young Men

The electrocardiogram (ECG) at rest and during orthostasis and exercise in 51 healthy men 18-19 years of age without history or symptoms of heart disease, but with T wave aberrations in the ECG (group T) were compared to the normal ECGs of 112 controls of the same age. These aberrations (which literature suggests to be due to organic heart disease) consisted of either a notch in the T wave, especially in the midprecordial leads, that sometimes became inverted, or a low T wave without concomitant ST depression. The T wave aberrations at rest in group T were similar to what 25% of the controls evidenced during orthostasis (group B). Both group T and group B had signs of increased sympathetic tone at rest with a higher heart rate and systolic blood pressure than did the subjects with normal ECG both at rest and during orthostasis. These T wave aberrations disappeared for the majority during exercise. Both group T and group B had prolonged QTc intervals. Group T had increased R wave amplitudes which did not correlate to the severity of the T wave aberration or to systolic blood pressure. Our opinion is that primary T wave aberrations in the majority of these young men were because of increased sympathetic tone.