Exercise and Depression in the General Population

Question 1

cross-section studies

Answer 1

• > cross-sectional (observational) study compares different population groups at a single point in time
• > yoshiuchi et al., 2006 showed that daily step count and daily duration of moderate intensity PA were significantly and inversely correlated with depression
• > physical activity goes up, depression symptoms go down

Question 2

longitudinal studies

Answer 2

• > longitudinal study researchers conduct several observations of the same subjects over a period of time
• > paffenbarger et al. (1994)
• > participants were split into 1 of 3 weekly energy expenditure (EE) categories, <1000, 1000-2499, 25000+ kcal/week
• > those with the highest weekly EE were 28% less likely to develop depression than the lowest weekly EE group
• > those with moderate weekly EE were 17% less likely to develop depression than the lowest weekly EE group

Question 3

effects of exercise training on older patients with major depression (blumenthal et al.)

Answer 3

background: exercise training may reduce depressive symptoms in older patients with major depressive disorder (MDD)
objective: to asses the effectiveness of an aerobic exercise program compared to standard medication (antidepressants)
methods: 156 men & women with MDD randomly assigned to exercise, antidepressant medication or combined exercise and medication

treatment period: 16 weeks

primary outcome: better scores of Hamliton Depression Scale and Beck Depression Inventory

secondary outcome: aerobic capacity, life satisfaction, self-esteem, anxiety and dysfunctional cognitions

Question 4

conclusion of exercise training and major depressive disorder

Answer 4

• > an exercise training program may be considered an alternative to antidepressants for treatment of depression in older persons
• > after 16 weeks of treatment, exercise was equally effective in reducing depression among patients with MDD

Question 5

statistically significant change

Answer 5

=> usually focus on statistical significance to discuss effectiveness of an intervention, meaning the change is likely not by chance. however, this does not necessarily mean that it is clinically important

=> Centre for Epidemiological Studies - Depression (CES-D)

= or > means at risk for depression

=> statistical significance would be comparing the mean of two groups and seeing if there is a difference

=> this does not mean their score improved clinically

Question 6

prenatal depression

Answer 6

• > affects up to 20% of all pregnancies
• > 19% will continue to have depressive symptoms postpartum
• > can negatively impact growing fetus: preterm birth, intrauterine growth restriction, early cessation of breastfeeding

Question 7

prenatal depression treatment options

Answer 7

=> pharmacological treatment options are often avoided

=> most women go untreated

=> recent literature has shown that exercise may prevent prenatal depression

Question 8

clinically reliable change criteria

Answer 8

reliability: if measures were repeated in the same population you would see the same results

clinically important: practical importance of the treatment effect being observed

Question 9

purpose and method of physical activity and prenatal depression study

Answer 9

purpose: to determine if prenatal exercise during pregnancy can treat depression among women who enter pregnancy at risk for depression and if exercise can have a clinically reliable change on depression risk during pregnancy
method: randomized controlled trial: exercise group and standard care control group

group fitness class 3 / per week

aerobic training and resistance exercises

baseline: 9-12 weeks

completion 36-38 weeks

at baseline and at the end, completed the CES-D

Question 10

calculating the clinically reliable change criteria

Answer 10

• the reliability of the measurement (Cronbach’s alpha) (0.752)
• standard deviation for the current population
• standard error of difference between scores at 2 time points (3.6)
• gives clinically reliable change criteria (7.09 -> 7 - how many of the treatment patients reduced the depression symptom on the CES-D by atleast 7 points)

Question 11

results of exercise and prenatal depression study

Answer 11

• 61 women included (36 exercise, 25 control)
• assessed potential confounding variables: age, pre-pregnancy BMI, smoking status, education level, occupation, previous miscarriage incidence, parity, weight gain
• no difference observed from intervention and control groups
• >7 point decrease in CES-D scores and below 16, control reduced score by 3 points
• 22 women (61%) had a score decrease by 7 points in the EG compared to 8 women (32%) had a score decrease by 7 points in the CG (chi square p<0.05)

Question 12

findings on prenatal exercise and depression

Answer 12

• prenatal exercise may have both a statistical and clinically reliable treatment effect on depression risk
• prenatal exercise may be prescribed to treat women who enter pregnancy with depression risk
• exercise can increase the likelihood of achieving the clinically reliable threshold

Question 13

strengths and limitations of prenatal exercise and depression

Answer 13

strengths

1. first study to calculate and apply clinically reliable change criteria for this population; calculation can be used for other outcomes
2. only included women with a CES-D score greater or equal to 16

limitations

1. convenience sample used
2. group dynamics not assessed

Question 14

future steps for prenatal exercise and depression studies

Answer 14

• design a prenatal exercise intervention based study with an priori sample size calculation specifically for women at risk for prenatal depression
• follow up in the postpartum period

Question 15

by providing clinical evidence for prenatal exercise and depression

Answer 15

• inclusion of prenatal care
• treatment option
• support women and the next generation in leading a healthy lifestyle

Question 16

review of exercise for depression (cooney et al.)

Answer 16

• found mean difference of -0.62 favoring exercise
• concluded that the antidepressant effect of exercise may be small

Question 17

stepwise reduction effect over time

Answer 17

• pooled standardize mean difference (SMD) from:
• 1.10 in 2001
• 0.82 in 2009
• 0.67 in 2012
• 0.62 in 2013
• hence an effect of 0.6 suggests that the experiemental group has a net gain of 23% over the control group
• the score of the average person in the experimental group exceeds the scores of 73% of the control group

Question 18

demystifying the shrinkage phenomenon

Answer 18

• applying the following rule to the data: only examine studies where exercise is compared to a passive (non-exercise) control
• pool SMD is raised from -0.62 to -0.90

Question 19

how does exercise affect coping efficacy in those with depression?

Answer 19

• depression is associated with low efficacious beliefs like, low confidence in ability to achieve outcomes, regulate negative cognition, cope
• exercise leads to improved coping efficacy in those with depression

Question 20

how does chronically high levels of cortisol relate to episodic memory deficits and reduced hippocampal volume?

Answer 20

• depression is often associated with episodic memory impairment, reduced hippocampal volume, high or dyregulated cortisol secretion
• episodic memory processing occurs in the hippocampus and surrounding areas

- chronically high levels of cortisol independently implicated in both episodic memory deficits and reduced hippocampal volume

Question 21

how does exercise affect episodic memory?

Answer 21

• in those with depression memory function improves with successful treatment
• since exercise is a efficacious treatment, exercise has been shown to improve episodic memory in healthy young adults

Question 22

how does exercise affect cortisol secretion?

Answer 22

• in those with depression cortisol secretion is normalized with successful treatment
• since exercise is an efficacious treatment, exercise does decrease cortisol secretion in healthy adults

Question 23

how does exercise affect episodic memory and hippocampal volume?

Answer 23

• the effect of exercise on episodic memory and hippocampal volume may be mediated through cortisol

Question 24

examination for exercise as a treatment for depression

Answer 24

procedure: participants who met criteria were randomized into a 12 week aerobic exercise or stretching intervention

participants attend sessions 3x per week for 30-40 mins

aerobic exercise group = moderate intensity, at 40-70% of Heart Rate Reserve

stretching group = mild-intensity stretching

measures:

depression - Beck Depression Inventory (BDI-II) and The Montgomery-Asberg Depression Rating Scale (MADRAS)

coping efficacy - depression coping self-efficacy scale

episodic memory - verbal recall task - uncued and cued recall

cortisol - salivary cortisol concentration at waking, 30 min post waking & before bed

cardiovascular fitness - modified Astrand-Ryhming cycle ergometer test

flexibility - YMCA Sit-and-Reach test

attendance

Question 25

results of BDI-ll after exercise treatments

Answer 25

Beck Depression Inventory: decreased in both groups at 6 and 12 weeks

decreased more in the aerobic exercise group

Question 26

results of MADRAS after exercise treatment

Answer 26

The Montgomery-Åsberg Depression Rating Scale: decreased in both groups at 12 weeks

decreased more in the aerobic exercise group

Question 27

results of coping efficacy after exercise treatment

Answer 27

Depression Coping Self-Efficacy Scale: increased in both groups at 6 and 12 weeks

coping efficacy improved more in the stretching group

Question 28

results of un-cued recall after exercise treatment

Answer 28

Un-cued recall: improved in both groups at 6 and 12 weeks

improved more in the aerobic exercise group

Question 29

results of cued recall after exercise treatment

Answer 29

cued recall: improved in both groups at 6 weeks and leveled at 12 weeks

cued recall improved more in the aerobic exercise group

Question 30

results of CAR after exercise treatment

Answer 30

cortisol awakening response: decreased in both groups at 6 weeks

decreased in aerobic exercise group

increased in stretching group at 12 weeks

no significant time effect

significant time*group effect (p=0.042)

Question 31

clinical significance of exercise treatment for depression

Answer 31

• recent research on the BDI has shown clinical significance
• clinically important reduction in symptoms:
• > cut-off score of 14.29 must be crossed in order to move from being depressed to being non-depressed
• > change in score greater than the reliable change index (RCI) of 8.46 must be observed
• both exercise and stretching groups passed the cut-off
• only exercise group had a change score greater than the RCI (10.6 vs 6.4)

Question 32

conclusion of exercise treatment for depression

Answer 32

• participants in the aerobic exercise group showed significant reductions in depression and significant improvements in coping efficacy and episodic memory
• however, these benefits also occured albeit to a lesser extent in the stretching group
• study was insufficiently powered to detect statistically signifcant small to medium effects that favored the exercise condition
• adherence was a problem in stretching group
• exercise group satisfied both criteria for a clinically important change in depression
• both aerobic exercise and stretching seem to be good treatments for depressions with positive changes to coping efficacy and episodic memory

however, stress (cortisol) was only positively influenced by aerobic exercise

Question 33

kynurenine (KYN)

Answer 33

• kynurenine produced mainly in the liver in response to stress that travels to the brain, where it’s linked to neuroinflammation, cell death and depression
• exercise causes your muscles to increase levels of a protein called PGC-1alpha1, which in turn leads to a higher level of an enzyme (KAT) that converts kynurenine into kynurenic acid (KYNA) which can’t cross into the blood-brain barrier, so unlike kynurenine it can’t get into the brain and damage it

Question 34

is exercise effective as pharmacological products in reducing depression?

Answer 34

• exercise is just as effective as pharmacological products in reducing depression
• implications: free and offeres other health benefits (fitness)