Robert Jordal

Dermal excretion of iron in intensely training athletes

The iron concentration in sweat and serum and related variables (transferrin saturation percentage, hemoglobin concentration) was measured in two groups of distance runners, each consisting of ten persons. In the first group unclear sweat was collected from the back of the athletes during cycling (without previous washing). The iron concentration (means +/- SEM) was 5.2 +/- 1.0 mumol/l of sweat. In the second group the sweat collection was performed similarly, but following elimination of the very first sweat from the site of collection (back) before three consecutive samples were taken. The iron concentration of the three samples was 3.6 +/- 1.1, 2.3 +/- 0.2 and 2.4 +/- 0.3 mumol/1. There was no statistically significant difference between the consecutive samples on the p less than 0.001 level. These results are in accordance with the lowest values found in the literature. There was no correlation between the iron concentration in sweat and in serum of the 20 persons. Seven of the runners had transferrin saturation percentages below 20, suggesting a possible iron deficiency. A daily loss in sweat of more than 18 mumol (1 mg) is possible in these runners training 125-350 km/week all the year round. The dominating iron loss of male endurance athletes is probably through the sweat.

Muscle cell leakage due to long distance training

SummaryAbnormal myoglobinemia (above 77 Μg/1) and free hemoglobin in plasma were found in 16 runners and in nine non runners immediately following distance running. The same abnormalities were found in six elite rowers following rowing. In parallel with the rise in myoglobin and free hemoglobin a rise was found in serum concentrations of cellular enzymes (LDH, CK, ASAT, alkaline phosphatase) and of various metabolites. We found no proteinuria nor casts in the urine. Non runners had a higher rise in serum myoglobin than runners. Competitive running caused a rise in the serum concentration of the heart specific fraction of creatine kinase in seven of the nine (healthy) elite runners. The abnormal findings are only explainable on the basis of leakage of proteins from muscle cells to the circulation in otherwise healthy, well trained persons. Myoglobinemia and a transient rhabdomyolysis is a common phenomenon in long distance running, but evidently also occurs in distance rowing. Three months of running training prevented most of the muscle damage from relaxed jogging in the nine previous non runners. Neither the observed myoglobinemia nor the hemoglobinemia resulted in any significant loss of iron in the urine.

High prevalence rates of adult silent coeliac disease, as seen in Sweden, must be expected in Denmark.

Aim: To disclose the prevalence of adult “silent” coeliac disease in Denmark and Sweden. Experimental design: 1573 Danish and 1866 Swedish healthy blood donors were screened for the presence of serum anti‐gliadin antibodies (AGA) by enzyme‐linked immunosorbent assay. AGA‐positive serum samples were further analysed for IgA anti‐endomysium antibodies (EmA) by indirect immunofluorescence microscopy. Main results: The Danish donor population had a higher mean age than the Swedish (41.4 years versus 37.6 years) and a higher proportion of females (41% versus 32%), and had a lower mean level of AGA (17.3 units versus 20.6 units). Sixty‐one (3.9%) Danish donors had AGA above the cut‐off limit, and four of these also had positive EmA tests. Sixty (3.2%) Swedish donors had AGA above the cut‐off limit, and five of these also had positive EmA. Coeliac pathology was proven by biopsy in all five coeliac disease‐suspected Swedish donors. No small intestinal biopsy was performed in the coeliac disease‐suspected Danish donors. Conclusions: Based upon the finding of EmA in AGA‐positive serum samples, silent coeliac disease may be suspected in 1 per 394 Danish blood donors (2.5 per 1,000). A similar rate was proven in 1 per 373 Swedish blood donors (2.7 per 1,000), indicating no major differences in the prevalence of adult silent coeliac disease between the two neighbouring countries.

Therapeutic effect of exercise on hypertension

SummaryArterial blood pressure, total peripheral resistance (TPR), plasma catecholamine and other hormone concentrations were measured or estimated during, and 4 h following, a 20-min exercise test on the bicycle ergometer in 10 women with marginal (borderline) hypertension. Each woman served as her own control by repeating the whole procedure, except for the exercise test, on another day. Median and 80% range was used: M (0.8 R). Compared with the control, the exercise reduced the driving blood pressure from 103 (94–110) to 95 (80–100) mm Hg and the TPR from 1.13 (0.96–1.40) to 0.91 (0.79–1.11) PRUS — both reductions being statistically significant with two-sided P<0.05 for at least 4 h. — The reduced nervous and humoral sympathetic activity following aerobic exercise seems capable of explaining the low TPR, and the continuous rise in the muscular vasodilatator dopamine may be of importance.

β-Endorphin and ACTH in Plasma during Attacks of Common and Classic Migraine

Plasma levels of b-endorphin and ACTH were measured during and outside migraine attacks in 17 patients with common migraine and 11 patients with classic migraine. Specific radioimmunoassays for b-endorphin and ACTH were used. The b-endorphin assay did not cross-react with b-lipotropin. In common migraine, median plasma b-endorphin was 3.3 pmol/l (95% confidence limits: 2.5–4.0 pmol/1) during attacks and 2.9 (2.4–3.2) pmol/l in the headache-free period. In classic migraine, plasma b-endorphin was 3.2 (1.4–4.3) pmol/l during attacks and 2.4 (1.1–3.65) pmol/l outside attacks. ACTH plasma levels were 15 (10.5–20) pmol/l during and 15.7 (13.4–17) pmol/l outside attacks in common migraine. In classic migraine, plasma ACTH was 16 (7–36) pmol/l and 12.3 (8–28) pmol/l respectively. No significant differences were found between attacks and headache-free periods in common or classic migraine. Accordingly, we could not add evidence to the theory of a dysfunction of the endogenous opioid system in migraine.

Red cell 2,3-DPG, ATP, and mean cell volume in highly trained athletes

Summary20 male elite long distance runners were compared to a control group of blood donors to determine the effect of training on red blood cells. The acute effects of exercise on red cells were investigated in 11 of the runners following a race of 15–30 km. The runners had elevated resting values of red cell 2,3-DPG (P<0.05) and mean cell volume (P<0.01); blood Hb and ATP were not different from concentrations in the control group. The red cell status of the athletes may be explained by an increased proportion of young erythrocytes in runners. No statistically significant changes in red cell 2,3-DPG, ATP, mean cell volume or blood Hb were found post exercise.

Iron status in young Danes. Evaluation by serum ferritin and haemoglobin in a population survey of 634 individuals aged 14-23 yr.

Abstract: Iron status was assessed by serum ferritin and haemoglobin in a population survey comprising 634 randomly selected urban Danes (312 males, 322 females) 14–23 yr old. At all ages, males had significantly higher serum ferritin and haemoglobin values than females. Males: median serum ferritin displayed a steady increase with age from 33 to 109 μg/l (rs=0.53, p<0.0001). The prevalence of absent mobilizable body iron stores (serum ferritin <13 μg/l) was 3.5% at 16–17 yr of age, gradually declining to 0% at 22–23 yr. None of the males had iron deficiency anaemia (serum ferritin <13 μg/l and haemoglobin <129 g/l). Females: median ferritin values displayed a slight increase with age from 28 to 39 μg/l (rs=0.19, p<0.001). The prevalence of absent iron stores was 12.5% at 16–17 yr of age, declining to 6.6% at 22–23 yr. The prevalence of iron deficiency anaemia (serum ferritin <13 μg/l and haemoglobin <121 g/l) was 4.7% at 16–17 yr of age, declining to 1.3% at 22–23 yr of age. Compared with surveys in other parts of Scandinavia, young Danes had slightly higher serum ferritin levels, and a lower prevalence of iron deficiency.

Serum ferritin in children and adolescents. Results from population surveys in 1979 and 1986 comprising 1312 individuals

Abstract: Iron stores were assessed by measurement of serum ferritin in a population survey comprising 436 randomly selected urban Danish schoolchildren (219 boys, 217 girls) 7 to 17 years old. Median ferritin values were similar in boys and girls 7 to 13 years old, while 14‐ to 17‐year‐old boys had significantly higher values than girls of similar age (p< 0.0001). Boys had stable median ferritin values from 7 to 15 years of age, after which a significant rise was found from 16 to 17 years of age (p<0.01). Girls had unchanged median ferritin values from 7 to 11 years of age, after which a significant decrease was found from 12 to 17 years of age (p<0.01). The frequencies of low ferritin values < 16 μg/1 (indicating absent iron stores) were: Children 7 to 11 years, 1.0%. Boys 12 to 15 years, 4.5%; 16 to 17 years, 0%. Girls 12 to 15 years, 7.6%; 16 to 17 years, 16.7%. Ferritin levels in the reported 1986 survey were significantly higher than those obtained in a similar survey in the same area in 1979. The results indicate an overall increase in iron stores in Danish schoolchildren and adolescents during 1979–1986, possibly due to an increase in the consumption of meat, and in the use of vitamin‐mineral supplements containing iron.