Participants will be asked to walk for exercise in their community five days/week. Participants will be instructed to begin with 10-15 minutes of walking exercise/session in the first month of the intervention and to increase exercise duration by five minutes/session each week, facilitating reasonable but steady progress toward the goal of 30 minutes per session.

Self-reported pain in past 7 days will be measured by 6 questions in PROMIS Pain Interference Short Form; the questions measure severity of pain and use a 5-point scale (1=not at all; 2=a little bit; 3=somewhat; 4=quite a bit; 5=very much) whose sum can be transformed to a normalized T-score.

Self-reported sleep short form (8a) that assesses the pure domain of sleep disturbance in individuals aged 18 and older. Each item on the measure is rated on a 5-point scale (1=very good; 2=good; 3=fair; 4=poor; and 5=very poor) with a range in score from 8 to 40 with higher scores indicating greater severity of sleep disturbance whose sum can be transformed to a normalized T-score.

Gait speed will be assessed in by the 6 Minute Walk test, which measures the amount of distance the participant can complete on a standard walking course in six minutes without running or overexerting themselves. Gait speed will be measured by approach used in the National Health and Nutrition Examination Survey; participants will be asked to finish a 20-foot walking test and gait speed will be calculated as (20×0.3048 meter)/(time (seconds) to finish test).

Physical function will be assessed by the the Short Physical Performance Battery (SPPB). This battery assess functional performance on different tasks including timed short distance walk, repeated chair stands, and a balance test. Additionally, isometric grip strength, a commonly used measure of upper body skeletal function, will be assess with a hand held dynamometer.

The 10-item Treatment-induced Neuropathy Assessment Scale (TNAS) will be used to evaluate the severity and impact of peripheral neuropathy on daily functioning at baseline and following or during after chemotherapy treatment. All items are measured based on a 10-point scale. Scores of all items are summed, with higher scores indicating greater neuropathy. Two subscale scores will be calculated to evaluate symptoms related to sensory or interference dimensions. Sensory subscale score will be the mean of 6 sensory items: numbness, tingling, pain, hot or burning, feelings of coldness and disturbed sleep. The interference subscale score - the mean of 3 interference items: trouble walking, trouble with balance and difficulty using hands.

Self-administered questionnaire to assess habitual physical activity through three components: work activity, sport activity, and leisure activity. The Modified Baecke Questionnaire measures habitual activity in older adults, which includes questions on household activities, sports and leisure time activities. Free-living physical activity at baseline and follow-up will be measured using an Apple Watch. Adherence to walking exercise intervention will be measured based on four criteria: total walking minutes, total walking minutes within assigned target heart rate zone, percentage of prescribed walking minutes completed per week, and percentage of prescribed walking minutes within the target heart rate zone per week.

The FACT-B is a 37-item instrument designed to measure five domains of HRQOL in breast cancer survivors: Physical, social, emotional, functional well-being as well as a breast-cancer subscale (BCS). Each item on the measure is rated on a 5 point Likert-type scale (Not at all; A little bit; Somewhat; Quite a bit; and very much).

The Perceived Stress Scale (PSS-10) covers feelings and current life situation, both of which are measured on a 5-point Likert scale (0 = never, 1 = almost never, 2 = sometimes, 3 = fairly often, 4 = very often); higher scores indicate higher perceived stress.

The Gratitude Questionnaire-6 (GQ-6) is designed to measure four facets of dispositional gratitude: (a) intensity, (b) frequency, (c) span and (d) density. Each item is rated on a 7-point Likert-type scale ranging from 1 (strongly disagree) to 7 (strongly agree). Scores range from 6 to 42, with higher scores implying a greater level of dispositional gratitude and lower scores indicating a decreased disposition in gratitude.