Exercise and Insomnia Study: The Effects of 1 Week of Exercise Training on Insomnia Severity

Inclusion Criteria: 1. ISI ≥ 10 2. Age 18-55 years 3. Clinically defined Insomnia (i.e., meeting DSM-5 criteria for insomnia disorder) 4. Psychiatric health, aside from treated anxiety and depression determined by participant self-report and instruments described below. Exclusion Criteria: 1. Unstable acute or chronic medical conditions. Examples include, but are not limited to, central nervous system disorders (e.g., head injury, seizure disorder, multiple sclerosis, tumor), cardiovascular or hemodynamically significant cardiac disease, renal failure, diabetes. Individuals with well-controlled health conditions that do not affect sleep or well-being (e.g., asthma, high blood pressure, diabetes, or ulcers) will not be excluded. 2. Women who are pregnant, nursing, or are planning on becoming pregnant in the next three months. 3. Current untreated major syndromal psychiatric disorders: Specific exclusionary self-reports include: * Major depressive disorder * Dysthymic disorder * Bipolar disorder * Panic disorder * Obsessive compulsive disorder * Generalized anxiety disorder * Any psychotic disorder * Any current substance use disorder The investigators will NOT exclude participants for: * Untreated subsyndromal symptoms of depression or anxiety and currently treated and stable depression or anxiety disorder. * Past episodes of major depressive or anxiety disorder, provided the most recent episode ended at least six months before the diagnostic assessment * Simple phobia * Social phobia * Past eating disorders * Past substance use disorders * Specific learning disabilities 4. Other current sleep disorders, such as: * Insufficient sleep syndrome * Circadian rhythm sleep disorders * Narcolepsy * Restless legs syndrome * Obstructive sleep apnea * Current night shift work Other sleep disorders are diagnosed according to criteria listed in the DSM-5 and the International Classification of Sleep Disorders, 2nd Edition, 2005. These disorders are evaluated using a clinical interview with the Structured Interview for Sleep Disorders. 5. \> 0 on the Physical Activity Readiness Questionnaire (PAR-Q+), which represents an inability to safely perform exercise without medical approval or supervision. 6. High risk of sleep-disordered breathing indicated by ≥ 5 'Yes' responses on the STOP-Bang questionnaire, or ≥ 2 + male sex, ≥2 + BMI \> 35, or ≥2 + a neck circumference \>16 inches (females) or \>17 inches (males). 7. Obesity (BMI ≥ 30) 8. Indication of moderate/severe depressive or anxiety symptoms (score ≥ 10 on the Patient Health Questionnaire-9 \[PHQ-9\] or score ≥ 10 on the 7-item Generalized Anxiety Disorder Questionnaire \[GAD-7\], respectively) 9. Current treatment for insomnia 10. Suspected circadian rhythm disorder (delayed sleep phase: habitual bedtime ≥ 2:00 am or wake time ≥ 10:00 am; advanced sleep phase: habitual bedtime ≤ 9:00 pm or wake time ≤ 5:00 am) 11. Nocturnal shift-work (i.e., working between 12:00 am and 6:00 am) 12. Physically active (self-report of \> 2 sessions/week of structured physical activity or \>150 minutes/week of accelerometer-measured bouted moderate to vigorous physical activity)