Lecithin-cholesterol acyltransferase activity in patients with coronary artery disease examined by coronary angiography

This study grew out of observations of certain lecithin:cholesterol acyltransferase (LCAT) abnormalities in patients with atherosclerosis. We studied the interrelationships among LCAT, and total cholesterol, free and esterified cholesterol, cholesterol in individual lipoprotein fractions, triglycerides, phospholipids, free fatty acids, L-lactates in 90 angiographically examined patients with coronary artery disease and 30 control subjects without clinical manifestations of coronary artery disease. Results of the study showed LCAT activity to be significantly decreased (P<0.05) in patients with single-, double-, or triple-vessel disease than in disease-free subjects. LCAT was also found to follow the stage of coronary artery disease in angiographically examined patients. Decreased LCAT activity was accompanied by lower high-density lipoprotein cholesterol, elevated ratio of unesterified to esterified cholesterol, and increased levels of L-lactates, free fatty acids, and low-density lipoprotein cholesterol. Total cholesterol and triglycerides were within or slightly above the normal limits. The results show LCAT to be a significantly better indicator of the risk of coronary artery disease than either total cholesterol or triglycerides.Abbreviations LCAT lecithin:cholesterol acyltransferase - CAD coronary artery disease - UC/EC ratio of esterified to unesterified cholesterol - MI myocardial infarction - HDL high-density lipoprotein Correspondence to: A. Stavljenic-Rukavina     

Influence of heat stress and acclimation on maximal aerobic power

Summary Thirteen male volunteers performed cycle ergometer maximal oxygen uptake ( tests) in moderate (21 C, 30% rh) and hot (49 C, 20% rh) environments, before and after a 9-day heat acclimation program. This program resulted in significantly decreased (P<0.01) final heart rate (24 bt·min^–1) and rectal temperature (0.4 C) from the first to last day of acclimation. The was lower (P<0.01) in the hot environment relative to the moderate environment both before (8%) and after (7%) acclimation with no significant difference (P>0.05) shown for maximal power output (PO max, watts) between environments either before or after acclimation. The was higher (P<0.01) by 4% after acclimation in both environments. Also, PO max was higher (P<0.05) after acclimation in both the moderate (4%) and hot (2%) environments. The reduction in in the hot compared to moderate environment was not related to the difference in core temperature at between moderate and hot trials, nor was it strongly related with aerobic fitness level. These findings indicate that heat stress, per se, reduced the . Further, the reduction in due to heat was not affect be state of heat acclimation, the degree of elevation in core temperature, or level of aerobic fitness.     

卵磷脂胆固醇酰基转移酶基因单核苷酸多态性与冠心病脂代谢易感性的关联研究

目的：检测卵磷脂胆固醇酰基转移酶（lecithin cholesterol acyltransferase,LCAT）基因3个编码区单核苷酸多态位点在中国人群中的分布频率，并初步探讨它们与脂代谢和冠状动脉粥样硬化性心脏病（coronary atherosclerotic heart disease,CHD）易感性的关系。方法：采用聚合酶链反应－限制性片段长度多态性方法，分析209名正常人和203例CHD患者中608C／T、911T／C和1188C／T（参照序列：NM_000229）3个位点的多态性。结果：608C和608T等位基因频率分布符合Hardy-Weinberg平衡。CHD患者组608T频率显著低于正常人群（P＝0．034）。与无608T CHD患者相比，具有608T的CHD患者的血浆高密度脂蛋白胆固醇显著升高（P＝0．015）。911T／C和1188C/T在两组中均未检出。结论：LCAT基因608T等位基因与CHD患者较高的血浆高密度脂蛋白胆固醇水平相关联，可能与中国人CHD相关。911T／C和1188C／T在中国人群中非常罕见。     

Influence of body mass on maximal oxygen uptake: effect of sample size

Basal metabolic rate is scaled to body mass to the power of 0.73, and we evaluated whether a similar scaling applies when the O₂ transport capacity of the body is challenged during maximal exercise (i.e. at maximal O₂ uptake, V˙O _2max). The allometric relationship between V˙O _2max and body mass (y=a · x ^b, where y is V˙O _2max and x is body mass) was developed for 967 athletes representing 25 different sports, with up to 157 participants in each sport. With an increasing number of observations, the exponent approached 0.73, while for ventilation the exponent was only 0.55. By using the 0.73 exponent for V˙O _2max, the highest value [mean (SD)] for the males was obtained for the runners and cyclists [234 (16) ml · kg^−0.73 · min⁻¹], and for the females the highest value was found for the runners [189 (14) ml · kg^−0.73 · min⁻¹]. For the females, aerobic power was about 80% of the value achieved by the males. Scaling may help both in understanding variation in aerobic power and in defining the physiological limitations of work capacity. Accepted: 3 November 2000     

Effects of dichloroacetate on exercise performance in healthy volunteers

Dichloroacetate (DCA), a stimulator of the pyruvate dehydrogenase complex, decreases lactate levels and peripheral resistance and increases cardiac output. This study was performed to examine the effects of DCA on exercise performance in humans. Eight healthy male volunteers (age 20–28 years) were tested by bicycle spiro-ergometry using a microprocessor-controlled gas analysis system after infusion of DCA (50 mg/kg body weight) or saline. Prior infusion of DCA significantly reduced the increase of lactate levels during exercise when compared with infusion of saline (1.40±0.21 vs 2.10±0.09 mmol·l^–1 at 50% of the expected maximal working capacity, P<0.05; 8.53±0.45 vs 9.92±0.59 mmol·l^–1 at maximal working capacity, P<0.05). Oxygen uptake increased significantly after DCA when compared with saline from 7.5±0.4 vs 7.4±0.5 to 27.2±1.5 vs 23.7±1.7 (P<0.05) at anaerobic threshold and to 35.6±1.7 vs 30.5±1.0 ml · kg^–1 min^–1 (P<0.05) at maximal exercise capacity. Following DCA infusion the workload at which the anaerobic threshold was reached was significantly higher (160±7 vs 120±5 W, P<0.05) and the maximal working capacity was significantly increased (230±9 vs 209±8 W, P<0.05). In summary, DCA reduced the increase of lactate levels during exercise and increased oxygen uptake at the anaerobic threshold and at maximal working capacity, which was significantly increased. These results warrant further studies on a potential therapeutic application of DCA in patients with reduced exercise capacity.     

Influence of age on blood pressure recovery after maximal effort ergometer exercise in non-athletic adult males

This study investigated whether age influences blood pressure recovery after maximal exercise in adult males. Forty healthy, non-athletic adult males (20 young, aged 22 ± 3.46 years and 20 older, aged 48 ± 6.91 years) participated in the study. Subjects performed a maximal-effort ergometer exercise test. Peak oxygen uptake (VO_2max) was measured during the exercise protocol; heart rate (HR) and blood pressure (BP) were measured before exercise, during exercise (at 2-min intervals), and at the first minute of post-exercise recovery and subsequently at 2-min intervals until the recovery of BP. Results indicated that young adults had lower systolic blood pressure (SBP) recovery ratio (P < 0.05), lower SBP recovery time (P < 0.001), higher SBP% decline in 1, and 3 min (P < 0.001), and higher DBP% decline in 1, and 3 min (P < 0.05, <0.001) than the older adults, thus indicating faster BP recovery in young than older adults. A bivariate correlation test, revealed significant associations (P < 0.001, <0.01) between age and BP recovery parameters: percentage SBP decline in 1 and 3 min (27 and 39%), percentage DBP decline in 1 and 3 min (14 and 26%), third minute SBP ratio (22%), and SBP recovery time (72%). After controlling for factors affecting BP recovery such as resting SBP, percentage HR decline, VO_2max and delta SBP, the observed correlations reduced in SBP recovery time (29%; P < 0.002) but disappeared (P > 0.01) in the other BP recovery parameters. These data indicate the need to take into account, factors affecting BP recovery when interpreting the effect of age on BP responses after exercise in future investigations.     

Influence of acute submaximal exercise on T-lymphocyte suppressor cell function in healthy young men

A defect in T-lymphocyte suppressor cell function has been reported to occur in a number of autoimmune diseases. The influence of exercise on suppressor cell function has not been determined in individuals with autoimmune diseases, nor has it been determined in healthy individuals. The purpose of this investigation was to determine the effect of an acute bout of submaximal exercise on suppressor cell function in healthy males. Each subject (n=10) completed an exercise trial (E; 1 h of cycle ergometry at 70.6% of maximal oxygen uptake, followed by 2 h of recovery) and a resting trial (R; 3 h of seated rest), separated by at least 1 week. Treatment (E or R) order was counterbalanced. Venous blood samples were obtained pre-exercise (PRE), immediately after exercise (POST), and 2 h post-exercise (2HPOST), and at the same time points in the R trial. Lymphocyte phenotype percentages were determined by flow cytometry, while concanavalin- A-induced suppressor cell function was determined on peripheral blood mononuclear cells. No change was observed in the percentage of T-cytotoxic/suppressor cells. Suppressor cell function was significantly different between treatments, with the POST E value [mean (SD) 56.8 (1.6)%] being higher than the POST R value [41.7 (1.9)%]. No significant difference was observed 2HPOST. In conclusion, acute submaximal exercise resulted in a transient increase in suppressor cell function in healthy males. Accepted: 17 January 2000     

Effect of aerobic capacity on sweat rate and fluid intake during outdoor exercise in the heat

We measured the aerobic capacity, sweat rate and fluid intake of trained athletes during outdoor exercise and examined the relationship between aerobic capacity and thermoregulatory responses at high ambient temperatures. The maximal aerobic capacity ( ) of the subjects, nine male baseball players of college age, was determined by maximal exercise tests on a cycle ergometer. The subjects practised baseball regularly without drinking fluids from 1330 to 1530 hours. After 30 min rest, they played a baseball game with free access to a sports drink at 15°C from 1600 to 1830 hours. At a mean ambient temperature of 36.7 (SEM 0.2)°C, the mean percentage of body mass loss (m _b) and increase of oral temperature (T _o) from 1330 to 1530 hours was 3.47 (SEM 0.12)% and 0.81 (SEM 0.14)°C, respectively. The sweat loss from 1330 to 1830 hours was 56.53 (SEM 1.56)ml · kg^–1 of body mass (M _b) while the mean fluid consumption was 44.78 (SEM 2.39)ml · kg^–1 ofm _b, with recovery of 76.08 (SEM 2.81)% of sweat loss. The was significantly inversely correlated withm _b, fluid intake and rehydration amount, but showed no correlation withT _o. These results would suggest that at a given exercise intensity in subjects with a higher aerobic capacity body temperature is maintained with a lower sweating rate than that in subjects with a lower aerobic capacity.     

Aerobic exercise performance correlates with post-ischemic flow-mediated dilation of the brachial artery in young healthy men

In older healthy men, aerobic exercise capacity is related to postischemic flow-mediated dilation of the brachial artery (FMD), but corresponding data in a younger population is not available. In addition, whether submaximal aerobic exercise performance also correlates with this kind of vasomotor reactivity is not known. Therefore, in 15 nonsmoking young healthy men [age 27 (5) years; body mass index: 24 (2) kg/m²; mean (SD)] with different levels of ordinary physical activity, but not performing upper-extremity training, we measured FMD at 1 min after reactive hyperemia, and pulmonary oxygen uptake (O₂) at ventilatory anaerobic threshold (O₂AT) and at peak effort (peak O₂) during an incremental exercise on a treadmill. In our participants, FMD was 9.1 (3.4)%, O₂AT was 40.72 (5.92) ml/kg per min, and peak O₂ was 52.95 (8.13) ml/kg per min. Using bivariate Pearsons correlation, and in separate multivariate regression analyses, O₂AT and peak VO₂ showed a significant and reasonably good correlation with FMD (r=0.84, P<0.001 and r=0.77, P=0.001, respectively), independent of age, body mass index and serum total cholesterol (=0.77, P<0.001, R² of the overall model=0.79 and =0.70, P<0.005, R² of the overall model=0.69, respectively). Our data provide evidence suggesting that in young healthy men a higher submaximal and maximal aerobic exercise performance is associated with a greater FMD of peripheral conduit arteries.     

The effect of acute aerobic exercise on pulse wave velocity and oxidative stress following postprandial hypertriglyceridemia in healthy men

Oxidative stress is postulated to be responsible for the postprandial impairments in vascular function. The purpose of this study was to measure pulse wave velocity (PWV) and markers of postprandial oxidative stress before and after an acute bout of moderate exercise. Ten trained male subjects (age 21.5 ± 2.5 years, VO₂ max 58.5 ± 7.1 ml kg⁻¹ min⁻¹) participated in a randomised crossover design: (1) high-fat meal alone (2) high-fat meal followed 2 h later by a bout of 1 h moderate (60% max HR) exercise. PWV was examined at baseline, 1, 2, 3, and 4 h postprandially. Blood Lipid hydroperoxides (LOOHs), Superoxide dismutase (SOD) and other biochemical markers were measured. PWV increased at 1 h (6.49 ± 2.1 m s⁻¹), 2 h (6.94 ± 2.4 m s⁻¹), 3 h (7.25 ± 2.1 m s⁻¹) and 4 h (7.41 ± 2.5 m s⁻¹) respectively, in the control trial (P < 0.05). There was no change in PWV at 3 h (5.36 ± 1.1 m s⁻¹) or 4 h (5.95 ± 2.3 m s⁻¹) post ingestion in the exercise trial (P > 0.05). LOOH levels decreased at 3 h post ingestion in the exercise trial compared to levels at 3 h (P < 0.05) in the control trial. SOD levels were lower at 3 h post ingestion in the control trial compared to 3 h in the exercise trial (0.52 ± 0.05 vs. 0.41 ± 0.1 units μl⁻¹; P < 0.05). These findings suggest that a single session of aerobic exercise can ameliorate the postprandial impairments in arterial function by possibly reducing oxidative stress levels.     

Effect of concurrent aerobic and resistance circuit exercise training on fitness in older adults

The purpose of this study was to determine the physiological effects of a programmed accommodating circuit exercise (PACE) program consisting of aerobic exercise and hydraulic-resistance exercise (HRE) on fitness in older adults. Thirty-five volunteers were randomly divided into two groups [PACE group (PG) 8 men and 10 women, 68.3 (4.9) years, and non-exercise control group (CG) 7 men and 10 women, 68.0 (3.4) years). The PG participated in a 12-week, 3 days per week supervised program consisting of 10 min warm-up and 30 min of PACE (moderate intensity HRE and aerobic movements at 70% of peak heart rate) followed by 10 min cool-down exercise. PACE increased (P<0.05) oxygen uptake (O₂) at lactate threshold [PG, pre 0.79 (0.20) l min^–1, post 1.02 (0.22) l min^–1, 29%; CG, pre 0.87 (0.14) l min^–1, post 0.85 (0.15) l min^–1, –2%] and at peak O₂ [PG, pre 1.36 (0.24) l min^–1, post 1.56 (0.28) l min^–1, 15%; CG, pre 1.32 (0.29) l min^–1, post 1.37 (0.37) l min^–1, 4%] in PG measured using an incremental cycle ergometer. Muscular strength evaluated by a HRE machine increased at low to high resistance dial settings for knee extension (9–52%), knee flexion (14–76%), back extension (18–92%) and flexion (50–70%), chest pull (6–28%) and press (3–17%), shoulder press (18–31%) and pull (26–85%), and leg press (21%). Body fat (sum of three skinfolds) decreased (16%), and high-density lipoprotein cholesterol (HDLC) increased (10.9 mg dl^–1) for PG. There were no changes in any variables for CG. These results indicate that PACE training incorporating aerobic exercise and HRE elicits significant improvements in cardiorespiratory fitness, muscular strength, body composition, and HDLC for older adults. Therefore, PACE training is an effective well-rounded exercise program that can be utilized as a means to improve health-related components of fitness in older adults.     

The effect of physical activity and physical fitness on plasma adiponectin in adults with predisposition to metabolic syndrome

The purpose of this study was to measure changes in plasma adiponectin (ApN) over 24 months of exercise intervention in middle age adults with a predisposition to metabolic syndrome and to determine if changes in ApN were more affected by physical activity or physical fitness. Thirty-six subjects completed a 24 months home-based exercise program (cycling ≥ three times per week, ≥ 45 min/session at 50–65% of VO_2peak). Body composition, blood samples, and physical fitness were studied at baseline and after 12 and 24 months of participation in the study. The prescribed physical activity was monitored via self-reported exercise diary to determine MET levels, hours, and exercise compliance. Two-tailed repeated measures ANOVA and Spearman Rank Correlation Coefficients were used to detect significant differences and associations between the variables. ApN increased significantly (P < 0.05) after 12 months in males (n = 17; 5.3 ± 1.9–7.0 ± 3.0 μg ml⁻¹) but not in females (n = 9; 8.6 ± 3.8–11.5 ± 4.0 μg ml⁻¹). The net change in ApN over 24 months was significantly correlated to the net change in VO_2peak (physical fitness) (r = 0.66; P < 0.001), whereas exercise intensity was negatively correlated to ΔApN over 12 months (r = −0.4; P ≤ 0.04) and 24 months (r = −0.45; P ≤ 0.02). Based on our results, an improvement in cardiorespiratory fitness of 15% increased plasma ApN concentration. Our findings suggest that moderate physical activity performed over many months induces positive changes in the plasma ApN concentration in adults with a predisposition to metabolic syndrome.     

正常中国人及内源性高甘油三酯血症患者酰基辅酶A:胆固醇酰基转移酶基因多态性的研究

目的 研究酰基辅酶A:胆固醇酰基转移酶1(acyl-coenzyme A:cholesterol acyltransferase 1,ACAT1)基因rs1044925多态性是否与正常汉族中国人及内源性高甘油三酯血症(hypertriglyceridemia,HTG)患者血脂及载脂蛋白水平存在关联.方法 应用聚合酶链反应-限制性片段长度多态性分析法,对成都地区372名汉族人(267名正常人和105例内源性高甘油三酯血症患者)ACAT1基因rs1044925多态位点进行分析.结果 中国人ACAT1基因rs1044925多态位点C等位基因频率为0.137,显著低于中部和南部欧洲人的0.354(P＜0.05);HTG组和对照组C等位基因频率分别为0.153和0.137,两者之间差异无统计学意义.对照组AA基因型携带者血清低密度脂蛋白胆固醇(low density lipoprotein-cholesterol,LDL-C)和非高密度脂蛋白胆固醇(non-high density lipoprotein cholesterol,nHDL-C)水平均较C等位基因携带者(Ac和CC基因型者)显著升高[(3.25±0.68)mmol/L vs(3.03±0.87)mmol/L,P＜0.05;(3.80±0.71)mmol/L vs(3.23±0.82)mmol/L,P＜0.05],HTG组AA基因型携带者血清高密度脂蛋白胆固醇(high density lipoprotein-cholesterol,HDL-c)水平较C等位基因携带者显著升高[(1.00±0.28)mmol/L vs(0.87±0.17)mmoL/L,P＜0.05].结论 ACAT1 基因rs1044925多态性不仅与正常中国成都地区汉族人血清LDL-C、nHDL-C含量有关,而且还与内源性高甘油三酯血症患者血清HDL-C水平相关联.     

The effect of acute magnesium loading on the maximal exercise performance of stable chronic obstructive pulmonary disease patients

OBJECTIVE:

The potential influence of magnesium on exercise performance is a subject of increasing interest. Magnesium has been shown to have bronchodilatatory properties in asthma and chronic obstructive pulmonary disease patients. The aim of this study was to investigate the effects of acute magnesium IV loading on the aerobic exercise performance of stable chronic obstructive pulmonary disease patients.

METHODS:

Twenty male chronic obstructive pulmonary disease patients (66.2±8.3 years old, FEV₁: 49.3±19.8%) received an IV infusion of 2 g of either magnesium sulfate or saline on two randomly assigned occasions approximately two days apart. Spirometry was performed both before and 45 minutes after the infusions. A symptom-limited incremental maximal cardiopulmonary test was performed on a cycle ergometer at approximately 100 minutes after the end of the infusion. ClinicalTrials.gov: {"type":"clinical-trial","attrs":{"text":"NCT00500864","term_id":"NCT00500864"}}NCT00500864

RESULTS:

Magnesium infusion was associated with significant reductions in the functional residual capacity (-0.41 l) and residual volume (-0.47 l), the mean arterial blood pressure (-5.6 mmHg) and the cardiac double product (-734.8 mmHg.bpm) at rest. Magnesium treatment led to significant increases in the maximal load reached (+8 w) and the respiratory exchange ratio (0.06) at peak exercise. The subgroup of patients who showed increases in the work load equal to or greater than 5 w also exhibited significantly greater improvements in inspiratory capacity (0.29 l).

CONCLUSIONS:

The acute IV loading of magnesium promotes a reduction in static lung hyperinflation and improves the exercise performance in stable chronic obstructive pulmonary disease patients. Improvements in respiratory mechanics appear to be responsible for the latter finding.     

Influence of exercise on serum brain-derived neurotrophic factor concentrations in healthy human subjects

The effect of short-term exercise (15 min step-exercise) on serum brain-derived neurotrophic factor (BDNF) levels was evaluated in healthy human subjects. Results showed a short-term, significant increase in serum BDNF levels after exercise. Intra-individual differences in serum BDNF levels were remarkably small on the rest day and also when compared to rest values on the day of the exercise test. Inter-individual differences, on the other hand, were larger by comparison. The result of this study supports the need for larger sample size in studies on BDNF changes in psychiatric disorders or psychiatric drug effects.     

The effect of acute aerobic exercise on stress related blood pressure responses: a systematic review and meta-analysis

The beneficial impact of regular exercise on cardiovascular health is partly mediated by psychobiological mechanisms. However, the effect of acute exercise on psychobiological responses is unclear. Thus, we performed a systematic review of randomised controlled trials (RCTs) that examined the effect of acute aerobic exercise on blood pressure (BP) responses (the change from baseline to stress) to psychosocial laboratory tasks. Fifteen RCTs met inclusion criteria of which ten demonstrated significant reductions in post-exercise stress related BP responses compared with control (mean effect sizes for systolic and diastolic BP, 0.38 and 0.40). Studies involving greater exercise doses tended to show larger effects, with the minimum dose to show a significant effect being 30 min at 50% VO2max. No other moderators emerged from the examination of participant characteristics, research designs and stressor characteristics. In conclusion, an acute bout of aerobic exercise appears to have a significant impact on the BP response to a psychosocial stressor.     

The acute effect of marathon running on plasma lipoproteins in female subjects

Summary The acute effect of running a 42.2 km marathon race on plasma lipoproteins was investigated in 12 female subjects (aged 21 to 41 years). During the race there was a significant increase (P<0.01) in the concentration of total plasma cholesterol. The mean post-race concentration of high density lipoprotein cholesterol (HDL-C) was 64.0±16.2 (SD) mg 100 ml^–1, compared with 52.1±14.0 mg 100 ml^–1 before the race, representing a significant increase (P<0.002). There was no significant difference in the concentration of very low density lipoprotein (VLDL) or low density lipoprotein (LDL) before and after the exercise. The mean concentration of the cholesteryl ester moiety of the HDL increased from 43.7±12.3 to 54.3±15.7 mg 100 ml^–1 (P<0.002), while there was no significant change in the concentration of the unesterified cholesterol, phospholipid, triacylglycerol or protein moieties of the HDL. The relative proportions of apolipoproteins A-I, A-II, C and E remained unchanged during the exercise. The changes in the concentration of each of the lipoprotein fractions observed during the marathon varied considerably between subjects. The individual increases in the concentration of HDL-C ranged from 4.1 to 28.4 mg 100 ml^–1, while both increases and decreases in individual concentrations of VLDL and LDL as well as of total plasma cholesterol were observed. These observations suggest that women undergo greater changes in HDL-C concentration than men during acute exercise, while considerable variation between individuals occurs.     

Effect of exercise on the mitochondrial DNA content of peripheral blood in healthy women

Exercise decreases insulin resistance and increases maximal exercise capacity as estimated from maximal oxygen uptake (V˙O_2max). Recent reports have demonstrated that the mitochondrial DNA (mtDNA) content of blood is correlated with V˙O_2max in healthy subjects (mean age 31 years) and is inversely correlated with insulin resistance parameters. The aim of this study was to determine the effect of regular exercise on the mtDNA content in the peripheral blood of 16 healthy young women of mean age 24.8 (SD 6.2) years and 14 healthy older women of mean age 66.7 (SD 5.8) years. The exercise programme lasted for 10 weeks and consisted of three sessions a week, each of 1 h and aiming to attain 60%–80% of V˙O_2max. The mtDNA content of peripheral blood was measured by competitive polymerase chain reaction. The V˙O_2max had significantly increased following the exercise programme [from 33.1 (SD 3.4) to 35.2 (SD 3.4) ml · kg⁻¹ · min⁻¹ in the young and from 24.3 (SD 5.3) to 30.3 (SD 7.3) ml · kg⁻¹ · min⁻¹ in the older women, both P < 0.05]. Exercise decreased systolic blood pressure, and concentrations of triglyceride, low density lipoprotein-cholesterol (LDL-C), glucose and insulin in the blood of the young and of total cholesterol, LDL-C and glucose in that of the older women. High density lipoprotein-cholesterol (HDL-C) in the young women was increased by exercise. The mtDNA content significantly increased following the exercise programme in both groups [from 27.1 (SD 17.9) to 52.7 (SD 44.6) amol · 5 ng⁻¹ genomic DNA in the young and from 15.3 (SD 10.2) to 32.1 (SD 30.0) amol · 5 ng⁻¹ genomic DNA in the older women, both P < 0.05]. There was a significant positive correlation between the change in mtDNA content and the change in V˙O_2max (r=0.74 in the young and r=0.71 in the older women, both P < 0.01). In conclusion, 10 weeks of moderate intensity, regular exercise increased the mtDNA content in peripheral blood and decreased insulin resistance parameters. This data suggests that increase in the mtDNA content may be associated with increased insulin sensitivity. Accepted: 15 April 2000