The effects of power and stretch yoga on affect and salivary cortisol in women.

Yoga practice is known to improve well-being and decrease stress. However, acute yoga is understudied. This study investigated the effects of two different types of yoga on affect and salivary cortisol levels in college women. Thirty-three women aged 18-30 years each completed 1-hour sessions of power yoga and stretch yoga. Measures of affect and salivary cortisol were assessed before, during, and after each session. Participants perceived power yoga to be more pleasurable and energizing. Salivary cortisol significantly decreased after both yoga sessions. Thus, even one session of yoga may be effective in improving affect and decreasing stress in college women.

Impact of Acute Intermittent Exercise on Natural Killer Cells in Breast Cancer Survivors.

BACKGROUND: Current research examining the effect of exercise on immune responses in cancer survivors is limited. OBJECTIVE: The aim of this pilot study was to examine the effect of 1 bout of intermittent exercise on natural killer (NK) cell numbers in breast cancer survivors. METHODS: A total of 9 women with stage I to III invasive breast cancer who were 3 to 6 months posttreatment and 9 sedentary women without a history of cancer completed 10 three-minute intervals of aerobic exercise on the cycle ergometer at 60% of VO2peak (peak oxygen uptake). Whole blood samples were taken pre-exercise, immediately postexercise, and at 2 hours and 24 hours postexercise. NK cell counts were assessed using flow cytometry. RESULTS: In both groups, NK cell counts significantly increased immediately postexercise compared with pre-exercise (P = .004-.008) and returned to near pre-exercise levels during recovery (P = .129-.547). Absolute NK cell counts were significantly lower in breast cancer survivors immediately postexercise when compared with controls (P = .046). CONCLUSIONS: The breast cancer survivor group exhibited NK cell responses to 30 minutes of moderate-intensity intermittent aerobic exercise that were comparable with that in the group of physically similar women without a history of cancer. Immune changes related to cancer treatments may be related to the lower absolute NK cell counts observed in the breast cancer survivor group. Although the results of this study are preliminary in nature, they suggest that this type of exercise does not disrupt this aspect of innate immunity in recent breast cancer survivors, thereby supporting current exercise recommendations for this population.

Exercise in patients with breast cancer and healthy controls: energy substrate oxidation and blood lactate responses.

The aim of this study was to compare select aspects of exercise energy metabolism in patients with breast cancer with that of healthy controls across a variety of exercise intensities. Posttreated patients with breast cancer were matched with healthy women based on age, physical fitness level, and menopausal status. Subjects participated in low-, moderate-, and high-intensity submaximal exercise sessions that corresponded with 40% of maximal oxygen consumption (Vo(2max)), 60% Vo(2max), and 70% Vo(2max). Oxygen consumption and respiratory exchange ratio were taken during submaximal exercise sessions to determine substrate oxidation rates for carbohydrate (CHO) and fat. Blood lactate and blood glucose were also measured before and after each of the submaximal exercise sessions as indices of CHO metabolism. Results indicate that the patients with breast cancer had a significantly (P≤.05) lower CHO oxidation rate and higher fat oxidation rate at all exercise intensities compared with healthy women. The patients with breast cancer had a significantly (P≤.05) lower blood lactate response to exercise across all intensities compared with the healthy women. Glucose responses tended (P<.08) to be more elevated in patients with cancer both before and after the exercise sessions. The findings indicate that posttreated patients with breast cancer have augmented fat metabolism and a reduced CHO-based energy metabolism during submaximal exercise. It is unclear whether these changes are the result of the patient's cancer or their treatment regimen for the cancer.

Aerobic exercise intensity in breast cancer patients: a preliminary investigation.

PURPOSE: This study compared the heart rate (HR), rate of perceived exertion (RPE), and blood lactate (BL) responses to aerobic exercise between posttreated breast cancer patients and apparently healthy, age-matched controls. METHODS: Seven patients and 7 control subjects underwent a submaximal treadmill test for the estimation of Vo(2max). Exercise intensities of 40%, 60%, and 70% of Vo(2max) were calculated from the treadmill test and randomly examined between groups during three 9-minute exercise bouts on 3 different days. Independent samples t tests were used to examine the HR, RPE, and BL responses at each intensity between groups. RESULTS: No significant differences were observed between the control and patient groups for HR, RPE, and BL at 40% (101 +/- 9 vs 101 +/- 11 bpm, P = .979; 8 +/- 1 vs 9 +/- 3, P = .237; and 1.11 +/- 0.73 vs 1.26 +/- 0.64 mmol/L, P = .188, respectively) and 60% (127 +/- 17 vs 117 +/- 13 bpm, P = .523; 12 +/- 2 vs 11 +/- 3, P = .267, and 3.83 +/- 2.48 vs 2.23 +/- 1.65 mmol/L, P = .237, respectively) of Vo(2max) . At 70% of Vo(2max), no significant differences were found for HR (151 +/- 27 vs 135 +/- 13 bpm, P = .704) and RPE (14 +/- 1 vs 13 +/- 3, P = .181), but lower BL responses were observed in the patient group (7.70 +/- 1.62 vs 3.29 +/- 1.08 mmol/L, P < .0005). CONCLUSIONS: The results suggest similar HR, RPE, and BL responses between patients and control subjects at 40%, 60%, and 70% of Vo(2max) , except for BL at 70% of Vo(2max). The lower BL response in the patient group at 70% of Vo(2max) was somewhat unexpected. Further research is needed to confirm or refute the results of this study to allow for a clearer understanding of the physiological responses of breast cancer patients to aerobic exercise at moderate or higher intensities so that safer aerobic exercise prescriptions can be developed for this population.