PubMed Health⌕ Search

Biomedical subjects

M Loftin

Publications and source records attributed to M Loftin.

13 recordsLinked to original sources
PubMed2001

Scaling VO(2) peak in obese and non-obese girls.

OBJECTIVE: The conventional ratio method (milliliters O(2) per mass) typically is used to express VO(2) peak. The goal of the current study was to compare VO(2) peak of obese girls with normal-weight girls by ratio and allometric scaling methods. RESEARCH METHODS AND PROCEDURES: We compared VO(2) peak by ratio and allometric methods in 46 obese and 47 normal-weight girls. Indirect calorimetry was used to measure VO(2) peak during either treadmill running or walking. Regression analysis was used to determine coefficients for mass and stature for each group with ANOVA used to compare data between groups. RESULTS: The obese girls were taller and had higher values of body fatness (p < or = 0.05). Absolute VO(2) peak (liters per minute) was similar between groups; however VO(2) peak relative to mass was 50% lower (p < or = 0.05) in the obese girls. When VO(2) peak (milliliters per minute per kilogram) and mass were correlated, r = -0.48 was found in the obese group. Allometric scaling of logarithmic transformed stature and mass reduced this to r = -0.002, thus eliminating the bias associated with the ratio method. Adjusting VO(2) peak allometrically scaled for mass, stature, and the combination of mass and stature reduced the difference between groups from 50% (ratio method) to 10% to 11% (p < or = 0.05) with higher values found in the normal-weight girls. DISCUSSION: These results demonstrate the bias associated with the ratio method when comparing VO(2) peak in obese girls with VO(2) peak in normal-weight girls. Allometric scaling eliminated the bias and thus may reflect a truer comparative response.

Adolescent↗
PubMed2000

Sex differences in pain indices, exercise, and use of analgesics.

To understand better reported sex differences in sensitivity to pain, this study examined daily pain frequency and intensity, use of analgesics, physical activity, and both subjective and physiological response to acute pain in 18 men and 24 women, healthy people who provided information about their daily pain symptoms and physical activity before completing a cold pressor task. Compared to men, women reported more frequent and intense pain symptoms, as well as more frequent use of analgesics and lower physical activity. Women evinced higher physiological arousal during the cold pressor task but similar subjective pain. The findings highlight the different ways men and women cope with pain and the effect on their responses to acute pain.

Adaptation, Psychological↗
PubMed2000

Impact of significant weight loss on maximal oxygen uptake in obese children and adolescents.

BACKGROUND: The prevalence of pediatric obesity has increased over the past few decades in all ethnic, gender, and age groups. The treatment of obesity, especially in children with moderate to severe conditions, is difficult. In this study, we examined the impact of significant weight loss as a result of participation in a multi-disciplinary weight management program on maximal oxygen uptake (VO2max) in obese children and adolescents. METHODS: Eleven obese children and adolescents (7 to 14 years of age; mean age, 12.3 +/- 1.9 years) were enrolled in a weight management program at the Children's Hospital of New Orleans. The treatment program included a high-protein, very low-calorie diet (VLCD; protein intake, 1.5 to 2.0 g/kg of ideal body weight per day; and 800 kcal/d). Diets were supplemented with extra fluid, minerals, and vitamins. All subjects attended weekly 2-hour clinic sessions. During these sessions, they received nutrition instruction, participated in a moderate-intensity, progressive exercise program, and learned behavior-modification techniques. Weight, height, body mass index ([BMI]; wt/ht2), and VO2max by indirect calorimetry were obtained at enrollment and at the end of 10 weeks of treatment. RESULTS: There was a significant decrease in body weight after 10 weeks. The BMI decreased significantly from 34.1 +/- 4.8 on entry to 29.4 +/- 3.5 (mean +/- SD; P < 0.0001). Despite the significant weight loss, VO2max increased significantly (P < 0.001) from entry (19.2 +/- 3.0 mL/kg/min) to completion of 10 weeks (22.4 +/- 5.8 mL/kg/min). However, absolute VO2max L/min was unchanged. CONCLUSIONS: We conclude that relative VO2max mL/kg/min is significantly improved in obese youth after significant weight loss with a VLCD and moderate-intensity, progressive exercise. However, because absolute VO2max L/min was unchanged, this improvement seems to result from the reduction in total body weight as opposed to the effect of the moderate-intensity exercise intervention.

Adolescent↗
PubMed1999

The health benefits of physical activity in children and adolescents: implications for chronic disease prevention.

UNLABELLED: Clinical, epidemiological and basic research evidence clearly supports the inclusion of regular physical activity as a tool for the prevention of chronic disease and the enhancement of overall health. In children, activities of a moderate intensity may enhance overall health, and assist in preventing chronic disease in at-risk youth. The numerous health benefits of regular exercise are dependent on the type, intensity and volume of activity pursued by the individual. These benefits include reduction of low density lipoproteins while increasing high density lipoprotein; improvement of glucose metabolism in patients with type II diabetes; improved strength, self esteem and body image; and reduction in the occurrence of back injuries. In addition, a progressive, moderate-intensity exercise program will not adversely effect the immune system and may have a beneficial effect on the interleukin-2/natural killer cell system. Furthermore, by decreasing sedentary behaviors and, thus, increasing daily physical activity, individuals may experience many stress-reducing benefits, which may enhance the immune system. CONCLUSION: Moderate intensity exercise of a non-structured nature seems to facilitate most of the disease prevention goals and health promoting benefits. With new guidelines promoting a less intense and more time-efficient approach to regular physical activity, it is hoped that an upward trend in the physical activity patterns, and specifically children at risk for chronic disease, will develop in the near future.

Adolescent↗
PubMed1999

Effects of familial pain models on daily pain indices and performance during the cold pressor task.

To understand better the role of pain history in current response to pain episodes, this research examined pain-related indices from the patient's family of origin and their relationships to the patient's coping with acute pain. Participants were 42 healthy men and women who provided information about their own and their family's pain history and then were administered a cold pressor task. High frequency of family pain modeling was associated with higher frequency of current pain episodes, more types of pain, greater intensity, and also lower physiological arousal and subjective pain ratings during the cold pressor. The findings underscore the relationships between familial pain modeling and current pain-related functioning.

Acute Disease↗
PubMed1999

The impact of significant weight loss on resting energy expenditure in obese youth.

BACKGROUND: The prevalence of obesity in American youth is increasing and treating the condition is difficult. METHODS: We have developed a multidisciplinary weight-reduction program that includes a very low calorie diet followed by a hypocaloric diet, exercise, and behavior modification. Based on data collected at baseline and at the end of the acute intervention phase (10 weeks), we assessed the impact of the weight loss that resulted from participation in this weight reduction program on the resting energy expenditure and body composition of obese children and adolescents. RESULTS: There was a significant decrease in body weight and body fat as assessed by weight determinations and skin-fold measurements after 10 weeks. The body mass index decreased significantly from 33.8 on entry to 29.6 (P < 0.0001). Despite the significant weight loss, resting energy expenditure and lean body mass remained constant from entry until the completion of the acute phase. CONCLUSION: We conclude that a multidisciplinary weight-reduction program that combines a very low calorie diet followed by a balanced hypocaloric diet, with a moderate-intensity progressive exercise program and behavior modification is an effective means for weight-reduction in obese children and adolescents. Furthermore, fat mass is significantly reduced while lean body mass and resting energy expenditure are unaltered.

Adolescent↗
PubMed1998

Effects of frequency of pain report on subjective pain ratings of the cold pressor task.

Differences in methodology among studies using the cold pressor task have affected the level of pain reported by subjects. This study was designed to assess the effects of varying frequency of self-report on intensity of subjective pain ratings. In a sample of 108 subjects, significant differences in pain ratings were found between subjects who rated their pain at 50-sec. intervals and groups who rated at lower or higher frequencies. Analysis indicated that the frequency of reporting pain may influence the coping strategies used by patients with pain and should be considered carefully by researchers.

Adaptation, Psychological↗
PubMed1996

Heart rate response during handball singles match-play and selected physical fitness components of experienced male handball players.

Limited information is available concerning the exercise response during handball (HB) singles match-play. Also, few studies exist that have examined VO2 peak and body composition of HB players. The purpose of this study was to examine the heart rate (HR) response during match play and peak physiologic responses and relative fat in twelve experienced HB players. Peak physiologic responses were measured during treadmill running and body composition was assessed via hydrodensiotometry. During HB match-play, HR was measured and stored every five seconds using a Polar Vantage XL heart watch. Physical characteristics and peak physiologic responses included the following: Age (yrs) 47.2; BW (kg) 78.0; height (cm) 178.9; % fat 18.9; VO2 peak (ml.kg-1.min-1) 48.0; RER peak 1.03; HR peak (bpm) 183.1 and lactic acid peak (mmol.l-1) 10.3. During HB match-play, HR averaged 85% of peak during one hour of play. Moreover, 67% of match-play time, HR was > 80% of peak. When HR responses were examined over one hour of match-play (twelve, five minute blocks) only the first five minutes were significantly different (lower) than the other 55 minutes. The exercise intensity and the relatively stable HR response observed during HB suggests that this activity appears to be appropriate for meeting the American College of Sports Medicine guidelines to develop and maintain cardiorespiratory fitness.

Adult↗
PubMed1994

Comparison of a simulated 16.1-km time trial, VO2max and related factors in cyclists with different ventilatory thresholds.

Differences in cycling performance have been observed in cyclists with similar VO2max values yet different lactate thresholds. The purpose of the current study was to compare a simulated 16.1-km cycling time trial, VO2max and related factors in cyclists who significantly varied in ventilatory threshold. From an original group of 18 category III or IV cyclists, two groups of 6 cyclists were formed based on ventilatory threshold values as high (77 +/- 4% of VO2max-Group H) or low (68 +/- 2.8% - Group L). VO2max and a 16.1-km time trial were completed on a Velodyne trainer. No significant difference (p > or = 0.05) was noted between groups in VO2max (Group H 4.00 +/- 0.281.min-1, Group L 4.15 +/- 0.671.min-1), however significant differences (p < or = 0.05) were found in ventilatory threshold and time trial scores. Group H completed the time trial in 16.29 +/- 2.08 min while Group L averaged 20.93 +/- 3.03 min. Group H completed the time trial 28% more quickly by working at a significantly higher percentage of VO2max, a higher power output and a faster pedal rate than Group L. From a battery of physiologic and body composition parameters, the ventilatory threshold expressed as VO2 (l.min-1) was the best predictor (r = -0.76) of time trial performance in the 12 cyclists. The findings of this study indicate that the ventilatory threshold was superior to VO2max in discerning performance differences in a 16.1-km cycling time trial, and was the best predictor of the simulated time trial performance.

Adult↗
PubMed1993

Recent advances in the treatment of childhood obesity.

The multidisciplinary, four-phase approach, which includes PSMF, BEM, and MPE is successful in treating mild, moderate, and severe degrees of childhood and adolescent obesity. The MPE program is appropriate for use with PSMF and BEM due to its progressive nature, variety of options, and moderate intensity level. In addition, the MPE program is of sufficient intensity, duration, and frequency to promote a significant increase in estimated aerobic capacity (VO2max) and to promote the maintenance of lean body mass and resting energy expenditure. The short-term intervention of PSMF, BEM, and MPE also results in an improvement in body composition, lipid profiles, and IGF-1 and T3 levels. The 1200-calorie balanced diet, MPE, and BEM also provide a successful method of weight maintenance in children and adolescents, as indicated by further improvement in body composition at the 26-week measure. Additional studies are needed to assess the contribution of exercise to the maintenance of lean body mass and resting energy expenditure in obese children and adolescents. In addition, it will be important to assess long-term weight maintenance in obese adolescents who effectively lose weight in this multidisciplinary program.

Adolescent↗
PubMed1988

Effect of arm training on central and peripheral circulatory function.

The purpose of this study was to examine the effect of endurance arm training on metabolic and circulatory function during arm and leg exercise. Thirty-eight females (aged 18 to 35 yr) participated in the study, with 19 subjects in the training group and 19 in a control group. Both a specific and general training response was observed at the conclusion of the 5-wk training period. As a result of training, during peak arm exercise, significant increases (P less than 0.05) were observed for oxygen uptake (VO2), ventilation, cardiac output, stroke volume, arterial-venous oxygen difference, cumulative work, and total performance time. During peak leg exercise following arm training, significant increases (P less than 0.05) were observed for VO2, ventilation, cardiac output, cumulative work, and total performance time. Standardized partial regression coefficients were used to examine the relative influence of the metabolic and circulatory components which define VO2. Prior to training during arm work, the arterial-venous oxygen difference accounted for the largest proportion of variance in VO2; but after training, stroke volume contributed the largest portion of variance. On the other hand, during leg exercise, stroke volume accounted for the largest portion of variation in leg VO2 both before and after arm training. The data suggest that endurance arm training as prescribed in this study elicits significant circulorespiratory function adaptations to support improved performance in both arm and leg work. Further, the findings suggest both a specific and general training effect, with the more dominant effect specific to arm work.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗