Preserving muscle health and wellbeing for long-term cancer survivors

Contrasting characteristics of daily physical activity in older adults by cancer history

BACKGROUND

Using objectively collected physical activity (PA) data from the Baltimore Longitudinal Study of Aging, the authors tested whether patterns of daily activity and sedentary time differed by cancer survivorship in older adults.

METHODS

In total, 659 participants (mean age ± standard deviation, 71 ± 10 years; 51% women) who had self-reported information on cancer history were instructed to wear an accelerometer for 7 consecutive days. Accelerometer data were summarized into: 1) PA volume and 2) activity fragmentation (interrupted activity), expressed as both continuous and as dichotomized (low and high) variables. Participants were categorized into 4 groups by cross-classification of dichotomous PA volume and fragmentation. Multiple regression models were used to estimate differences in PA patterns by cancer history.

RESULTS

Cancer survivors averaged 0.12 fewer log-transformed activity counts per day (standard error, 0.05; P = .02) than individuals who reported no history of cancer after adjusting for demographics, behavioral factors, and comorbidities. Although fragmentation did not differ by cancer survivorship in the continuous model (P = .13), cancer survivorship was associated with 77% greater odds (odds ratio, 1.77; 95% confidence interval, 1.11-2.82) of having high (vs low) fragmentation and 94% greater odds (odds ratio, 1.94; 95% confidence interval, 1.13-3.33) of having combined low PA/high fragmentation (vs high PA/low fragmentation) relative to those with no cancer history.

CONCLUSIONS

The current findings suggest that cancer survivors engage in lower total daily PA and that they perform this activity in a more fragmented manner compared with adults without a history of cancer. These results may reflect the onset and progression of a low-activity phenotype that is more vulnerable to heightened levels of fatigue and functional decline with aging.

Regular voluntary running has favorable histological effects on doxorubicin-induced kidney toxicity in Wistar rats

Knowing the therapeutic effects of regular physical exercise on kidney toxicity induced by a single dose of doxorubicin (DOX) in animal models, the aim of this study is to verify the effectiveness of regular voluntary running on kidney histology after a prolonged DOX administration, mimicking a chemotherapy protocol. Thirty-four male Wistar rats were randomly divided into two clusters: DOX (n = 17) and SSS (sterile saline solution, n = 17), receiving a weekly intraperitoneal injection of DOX (2 mg/kg) or vehicle for 7 weeks, respectively. Two weeks after the last injection, five animals from each cluster (SSSG, n = 5; DOXG, n = 5) were euthanized, while the remaining ones were divided into sedentary (DOXsed, n = 6; SSSsed, n = 6) and active subgroups (DOXact, n = 6; SSSact, n = 6). Active animals were placed individually in cages with a running wheel for regular voluntary activity. After 2 months, the animals were euthanized and kidneys were histologically examined. Compared to SSSG, kidneys from DOXG revealed higher levels of damage, more collagen content and thickening of Bowman's capsule (p < .05). The levels of damage and thickness of Bowman's capsule increased in DOXsed as compared to DOXG (p < .05). Compared to DOXsed, the DOXact presented an overall improvement in kidney structure (p < .05), with a decrease in collagen content and of the thickness of Bowman's capsule. The results allow concluding that regular voluntary running attenuate the long-term harmful effects on kidney structure induced by a prolonged DOX treatment. These results, supporting the potential benefit of physical activity in patients under DOX treatment, need to be tested in humans.