Cancer Survivor Center

Selected physiological responses, including lactate kinetics, to cardiopulmonary exercise testing (CPET) were evaluated among a group of cancer survivors (CS, n = 55) and healthy controls (HC, n = 213). It was uncertain if lactate testing in a group of cancer survivors could provide useful information about training intensity. It was hypothesized that chemotherapy, radiation, surgery, physical inactivity or some combination thereof would alter the normal lactate kinetics (curvilinearity) in the relationship of lactate concentration versus power. Physiologic responses of CS (heart rate, blood pressure, O(2) saturation, RPE, lactate, VO(2peak), and peak power) during cycle ergometry were compared to HC. Comparisons (t tests and Chi-square) were made between the groups and shape of lactate plots were analyzed for determination of a breakpoint. Multiple logistical regressions were then utilized to identify factors related to the inability to determine lactate breakpoints. Lactate breakpoints were common to all but one HC whereas among the CS there was a small subset of subjects (n = 5) who did not show a lactate breakpoint. Group differences indicated that female CS were significantly older, had greater BMI's, and lower work capacity than HC. Males CS had significantly lower work capacity than HC. Multiple logistical regression analyses, in all instances, yielded no statistically significant models predictive of the inability to determine a lactate breakpoint. In this sample of CS and HC, physiological responses and lactate kinetics during CPET were similar while work capacity among the CS was lower. Because lactate breakpoints were found, lactate threshold could be determined for all but a few individuals. For those working with CS, CPET with ECG monitoring and lactate threshold measures should be considered for those wishing for precise and safe training intensities.

Changes in aerobic capacity were evaluated after 12 weeks of training among a motivated heterogeneous group of cancer survivors (N = 54 [41 women and 13 men]), living at moderate altitude. Changes in power at lactate threshold (PTlact), peak power (Ppeak), and peak oxygen uptake (VO2 peak) were evaluated in this group (average age, 53.8 ± 10.8 years) that completed a minimum of 12 weeks of an individualized exercise program (on average 5 days•week-1 for 47.5 ± 17.2 min•session-1). Daily exercise duration was based on the goals and functional capacity of each individual. Training intensity for each subject was based on heart rate (HR) value at lactate threshold (Tlact) obtained during a symptom-limited cardiopulmonary exercise test. Intensity was categorized into 5 ranges: recovery (60%–80% HR Tlact); endurance (80%–100% HR Tlact); threshold (100%–105% HR Tlact); intervals (105%–115% HR Tlact); and maximal efforts (≥ 115% HR Tlact). Overall compliance with the exercise prescription was ˜72% and subjects reported exercising within the 5 training ranges, 12.1%, 63.9%, 18.6%, 4.2%, and 1.2% of the time, respectively. After training, PTlact increased 9.5% (121.8 ± 43.5 vs 133.2 ± 34.1 W; P < 0.05), Ppeak increased 12.6% (175.5 ± 55.6 vs 195.6 ± 54.2 W; P < 0.05) and VO2 peak increased 11.4% (33.4 ± 12.5 vs 37.2 ± 10.4 mL•kg-1•min-1; P < 0.05). The results of this research indicate that: 1) cardiopulmonary exercise testing with lactate threshold determination was safe and effective in the evaluation and exercise prescription phase for a group of cancer survivors and 2) a training program based on 2 higher intensity workouts per week can elicit significant changes in aerobic capacity of a diverse group of cancer survivors.

PURPOSE: The purpose of this investigation was to: a) measure the physiological responses to clinical graded exercise testing among a group of cancer survivors (CS), b) compare those responses to a group of healthy age-matched controls (HC), c) examine the lactate kinetics of each group and d) determine whether these data would be useful for exercise prescription. METHODS: Heart rate (HR), blood pressure (BP), percent saturation (% sat), blood lactate, power at lactate threshold (PTlact), maximal power (Pmax) and maximal oxygen uptake ( O2 max) were measured using CS (36 females, 12 males, x = 53.4 ± 11.5 y, BMI = 25.9 ± 8.2) and compared to HC (x = 52.6 ± 10.0 y, BMI = 24.5 ± 4.0) who underwent graded exercise testing (GxT) using cycle or treadmill ergometry. The CS included individuals undergoing chemotherapy and radiation and those post-treatment and included 15 different types of cancer. Physiological parameters were compared using ANOVA. Curve fitting with polynomial regression and least squares analysis were applied to lactate profiles of each group and an ANCOVA was used for analysis. RESULTS: HR, BP and % sat response to GxT were similar between CS and HC, however peak HR values were significantly lower in the CS group (159.3 ± 21.3 vs. 172.7 ± 15.8 beats·min−1). Compared to HC's, CS had significantly lower O2 max (37.7 ± 10.8 vs. 47.3 ± 11.1 ml·kg−1·min−1), lower maximal power (174.5 ± 85.1 vs. 275.7 ± 105.9 W) and lower power at threshold (121.3 ± 50.2 vs. 180.8 ± 71.3 W). Lactate profiles were significantly altered (linear response rather than curvilinear) in cancer survivors who were not active prior to cancer diagnosis. Active CS and HC subjects had similar profiles in which a break point could be determined. CONCLUSIONS: Determination of HR and PTlact for training ranges is useful for CS who are active prior to or are active during their treatment but these measures may not be applicable for those who were sedentary prior to and/or inactive during treatment.