Effect of supervised and home exercise training on bone mineral density among breast cancer patients. A 12-month randomised controlled trial.

UNLABELLED: The ability of combined step aerobic- and circuit-training to prevent bone loss after breast cancer treatments was related to skeletal site and patients' menopausal status. Among premenopausal breast cancer survivors, a 12-month exercise intervention completely prevented bone loss at the femoral neck, whereas no exercise effect was seen at lumbar spine or at neither site in postmenopausal women. INTRODUCTION: The primary objective of this randomised clinical trial was to determine the preventive effect of supervised weight-bearing jumping exercises and circuit training on bone loss among breast cancer patients. METHODS: Of 573 breast cancer survivors aged 35-68 years randomly allocated into exercise or control group after adjuvant treatments, 498 (87%) were included in the final analysis. The 12-month exercise intervention comprised weekly supervised step aerobic- and circuit-exercises and similar home training. Bone mineral density (BMD) at lumbar spine and femoral neck were measured by dual-energy X-ray absorptiometry. Physical performance was assessed by 2-km walking and figure-8 running tests, and the amount of physical activity was estimated in metabolic equivalent-hours/week. RESULTS: In premenopausal women, bone loss at the femoral neck was prevented by exercise, the mean BMD changes being -0.2% among the trainees vs. -1.4% among the controls (p = 0.01). Lumbar bone loss could not be prevented (-1.9% vs. -2.2%). In postmenopausal women, no significant exercise-effect on BMD was found either at the lumbar spine (-1.6% vs. -2.1%) or femoral neck (-1.1% vs. -1.1%). CONCLUSIONS: This 12-month aerobic jumping and circuit training intervention completely prevented femoral neck bone loss in premenopausal breast cancer patients, whereas no effect on BMD was seen in postmenopausal women.

Micronutrients: interaction between physical activity, intakes and requirements.

The present literature review examines the following questions: (a) What is the evidence that micronutrient requirements are increased in physically active people? (b) Is there an association between physical activity and micronutrient intake? (c) Are there any significant differences between indices of micronutrient status between physically active and inactive people? The available data suggest that micronutrient requirements are increased in physically active people because of increased losses through sweat, urine and faeces, and an increased need for defence against free radicals. However the evidence is controversial, and it is not possible to make any quantitative estimations. Micronutrient requirements in moderately active people are not likely to be very much above the levels recommended for the general population. The intake of micronutrients increases with increasing energy intake. Therefore, physically highly active people (athletes) have higher micronutrient intakes than untrained subjects. However, moderate physical activity does not necessarily affect daily micronutrient intake. The available indices of micronutrient status do not support the belief that micronutrient status is compromised in highly trained athletes, even without use of dietary supplements. Hence, there are no reasons to believe that the situation would be different in people who are only moderately active. The results suggest that micronutrient status is adequate for health and functional performance in physically active people who follow a normal, mixed Western diet.

Indicators of vitamin and mineral status in athletes' blood: a review.

This review examines the hypothesis that vitamin and mineral status in athletes is inadequate for optimal sports performance. The review is based on indicators determined from blood and on studies published since 1980. Most of the studies did not find micronutrient status in athletes to be different from untrained controls. The serum ferritin concentration in females was lower than in males (27 vs. 78 micrograms.L-1), and the prevalence of low serum ferritin concentration was higher in female athletes than in untrained female controls (37 vs. 23%). Supplementation of water-soluble vitamins and iron was associated with an improvement in the corresponding indicators. Excluding a few studies with mildly anemic subjects, improvements in indicators of micronutrient status were not associated with enhanced athletic performance. Consequently, the levels of indicators of micronutrient status seen in athletes' blood were apparently compatible with optimal physical performance.

Chronic oral lactate supplementation does not affect lactate disappearance from blood after exercise.

This study tested the hypothesis that a 3-week oral lactate supplementation affects postexercise blood lactate disappearance in untrained male subjects. Fifteen men were randomly assigned to either a lactate supplementation (n = 8) or a placebo (n = 7) treatment. During the treatment period they drank an oral lactate or a maltodextrin (placebo) supplement twice a day. The lactate drink contained 10 g of lactate as calcium, sodium, and potassium salts. Blood lactate concentrations were studied before, during, and immediately after three exercise tests, both pre- and posttreatment. Peak lactate values for placebo (PL) or lactate (L) treatment groups during different tests were as follows: Test 1 PL, 13.49 +/- 3.71; L, 13.70 +/- 1.90; Test 2 PL, 12.64 +/- 2.32; L, 12.00 +/- 2.23; Test 3 PL, 12.29 +/- 2.92; L, 11.35 +/- 1.38 and were reached 3 min postexercise. The decrease in blood lactate during the long (30- to 45-min) recovery periods amounted to / 10 mmol/L. Blood lactate changes were highly reproducible. However, a 3-week oral lactate supplementation did not result in differences in lactate disappearance. This study does not support the hypothesis that regular oral lactate intake at rest enhances the removal of lactate during and following exercise, that is, not with the given lactate load and supplementation period.

Ubiquinone supplementation and exercise capacity in trained young and older men.

It has been suggested that ubiquinone improves exercise performance and antioxidant capacity. We studied the effects of ubiquinone supplementation (120 mg.day-1 for 6 weeks) on aerobic capacity and lipid peroxidation during exercise in 11 young (aged 22-38 years) and 8 older (aged 60-74 years), trained men. The cross-over study was double-blind and placebo-controlled. Serum ubiquinone concentration increased after supplementation (P < 0.0001 for treatment) in both age groups. The maximal oxygen uptake (VO2max) was measured using a direct incremental ergometer test. In the young subjects, the VO2max after placebo and ubiquinone treatment was 58.5 (95% confidence interval: 53.0-64.0) and 59.0 ml.min-1.kg-1 (52.2-66.8), respectively. The corresponding results in the older subjects were: 37.2 (31.7-42.7) and 33.7 ml.min-1.kg-1 (26.2-41.7) (P < 0.0001 for age group, P > 0.05 for treatment). In a prolonged test (60-min submaximal, then incremental load until exhaustion) time to exhaustion was longer after the placebo [young men: 85.7 (82.4-89.0), older men: 82.9 min (75.8-89.9)] than after ubiquinone [young men: 82.1 (78.5-85.8), older men: 77.2 min (70.1-83.7); P = 0.0003 for treatment]. Neither ubiquinone supplementation nor exercise affected serum malondialdehyde concentration. Oral ubiquinone was ineffective as an ergogenic aid in both the young and older, trained men.

Effects of low-dose iron supplementation in women with low serum ferritin concentration.

We studied effects of dose and treatment duration during low-dose iron supplementation in premenopausal, non-pregnant women, with initial serum ferritin and haemoglobin concentrations < 20 micrograms x l-1 and > or = 120 g x l-1, respectively. The study was randomized, double-blind and placebo-controlled. Three groups completed a 6-month study: placebo (n = 27), FE-9 (9 mg iron x day-1, n = 18) and FE-27 group (27 mg iron x day-1, n = 19). The supplement consisted of 11% heme and 89% inorganic iron. In FE-27, serum ferritin increased from (mean, 95% confidence interval) 11.8 (9.7; 14.4) to 25.3 (18.6; 34.4) micrograms x l-1 in 1 month, and remained stable after that (ANOVA: group effect, P = 0.0003). In both FE-9 and FE-27, blood haemoglobin levels increased from 136 (132; 140) to 142 (139; 145) g x l-1 in 1 month, remaining constant after that (group effect, P = 0.001). Hence, the 27 mg daily dose of organic/inorganic iron corrected both mild anaemia and storage iron depletion, whereas the 9 mg dose did not affect iron stores. Elongation of treatment duration above 1 month brought about only minor changes.

Healthy lifestyles of former Finnish world class athletes.

Recently, Sarna et al. (Med. Sci. Sports Exerc. 25:237-244, 1993) reported increased mean life expectancy in former world class athletes. Because lifestyle is associated with longevity, we have examined whether health habits of former Finnish male athletes (N = 1274; present mean age: 57.5, range: 36-94 yr) differed from those of noncompetitive referents (N = 788; mean age: 55.7, range: 39-87 yr). The athletes had represented Finland in international competitions in endurance (N = 177), power (N = 454), or other ("mixed") events (N = 643) from 1920-1965. Data on physical characteristics, sociodemographic factors, and health habits were obtained from questionnaires. All dependent variables in an analysis of covariance and in a logistic regression analysis were adjusted for age and occupation. Both leisure aerobic and work activity of all athlete groups was higher (P < 0.01) than that of referents. Compared with the referents, both power and "mixed" athletes were more prone to eat fruits and vegetables and to avoid vitamin supplements, but less prone to use butter and high-fat milk, and to smoke (odds ratios different from 1.0, P < 0.05). Also endurance athletes smoked less and drank less alcohol than the referents (P < 0.05). Higher leisure aerobic activity and less frequent smoking after athletic years might explain higher life expectancy of Finnish athletes.

Vitamins, minerals and supplementation in soccer.

Despite low mineral intakes in several groups of female 'ball-game' players, investigations of blood profiles and physical performance do not indicate any evident physiological benefits of micronutrient supplementation. Nevertheless, measurements of iron status are warranted, particularly in female athletes. Iron therapy may be beneficial for iron-depleted (serum ferritin < 12 micrograms l-1) individuals. In athletes with infrequent or irregular menstruation, supplementary calcium might help to preserve bone density.

Factors affecting iron status in non-pregnant women from urban south Finland.

Iron status was evaluated in 446 non-pregnant urban Finnish women, aged 17-50 years. The mean results (95% ranges) for blood haemoglobin concentrations, mean corpuscular volumes (MCV) and serum ferritin concentrations were 139 g/l (121-155), 89 fl (79-97) and 28 micrograms/l (7-120), respectively. Serum ferritin was < 12 and < 20 micrograms/l in 11% and 30% of the subjects, respectively. In analyses of covariance, high frequency of menstruation, prolonged menstrual bleeding time, blood donation and use of intrauterine devices had negative effects (P < 0.05) on iron status. Dietary habits or participation in very hard physical exercise did not affect iron status. Factors predicting low iron stores were evaluated in a logistic regression analysis. Blood donation (odds ratio and its 95% confidence interval: 2.53; 1.22-4.82) and very prolonged (> or = 8 days) menstrual bleeding (4.93; 1.63-14.9) increased the likelihood for low serum ferritin, whereas daily physical activity (0.02; 0.01-0.88) and use of multivitamin and mineral supplements (0.57; 0.33-0.98) were associated with higher concentration. In conclusion, blood losses increase the risk for iron depletion, while higher physical activity (presumably because of the positive effects on energy and iron intake) may prevent iron depletion.

Lack of association between indices of vitamin B1, B2, and B6 status and exercise-induced blood lactate in young adults.

By means of a 5-week vitamin B-complex supplementation, associations between indices of vitamin B1, B2, and B6 status (activation coefficients [AC] for erythrocyte transketolase, glutathione reductase, and aspartate aminotransferase) and exercise-induced blood lactate concentration were studied. Subjects, 42 physically active college students (18-32 yrs), were randomized into vitamin (n = 22) and placebo (n = 20) groups. Before the supplementation there were no differences in ACs or basal enzyme activities between the groups. The ACs were relatively high, suggesting marginal vitamin status. In the vitamin group, all three ACs were lower (p < 0.0001) after supplementation: transketolase decreased from 1.16 (1.14-1.18) (mean and 95% confidence interval) to 1.08 (1.06-1.10); glutathione reductase decreased from 1.33 (1.28-1.39) to 1.14 (1.11-1.17); and aspartate aminotransferase decreased from 2.04 (1.94-2.14) to 1.73 (1.67-1.80). No changes were found after placebo. Despite improved indices of vitamin status, supplementation did not affect exercise-induced blood lactate concentration. Hence no association was found between ACs and blood lactate. It seems that marginally high ACs do not necessarily predict altered lactate metabolism.

Effects of iron supplementation in female athletes with low serum ferritin concentration.

Low serum ferritin concentrations are commonly found in female athletes. By studying the effects of an 8-week iron or placebo supplementation in 31 female athletes (aged 17-31 years), with an initial serum ferritin concentration less than or equal to 25 micrograms/l and blood hemoglobin 120 g/l, we investigated whether low serum ferritin values hinder aerobic performance. Serum ferritin concentration increased from 14 (25th and 75th percentile: 11, 21) to 26 (18, 36) micrograms/l in the iron-supplemented group, but remained at a low 11 (9, 17) micrograms/l in the placebo group (group difference after supplementation: p = 0.001). Before supplementation, blood hemoglobin concentration was not different in the two groups. After supplementation, however, the concentration in the iron group was 139 (135, 144) g/l and 128 (126, 134) g/l in the placebo group (group difference: p = 0.001). Iron supplementation did not affect blood lactate concentration or VO2max during an incremental ergometer test. Hence, aerobic performance was not impaired in nonanemic female athletes with serum ferritin 25 micrograms/l.