The Impact of Overnight Active Temperature Regulation on Gut Microbiome, Inflammation, and Circadian Rhythm.

Inclusion Criteria: All Cohorts * 45 years of age or older * Self-reported poor sleep quality: PSQI score greater than 5 * Within 1.5 hours driving of the Greater Boston area * Have never used an Eight Sleep Pod (or similar device) ever * Post-enrollment hsCRP ≤ 10 µg/mL at Preparation Period blood panel. If Preparation Period hsCRP \> 10 µg/mL: triggers clinical review on a case by case basis; hard exclusion applies only at \> 30 µg/mL Weight ≥ 88 lbs * No MRI scheduled during the study period or within 1 week after study conclusion * No acute illness, injury, or dental procedure/cleaning within 3 months prior to study start * Non-smoker or previous infrequent (\<1 weekly) smoker who has ceased at least 3 months prior to study start * Predictable bowel movements: at least 3 weekly and no more than 3 daily bowel movements * Able to drive or be transported to a local lab facility at least three total times for blood panels * Willing to complete 3 blood panels (3-4 tubes of blood collected at each draw): no strong aversion to needles * Able to swallow a pill/capsule (approximately the size of the standard vitamin capsule) for internal core temperature monitoring * Stable diet for a minimum of 3 months prior to enrollment, with no planned major dietary changes during the study period * Stable medication regimen: no medication type or dose changes within 3 months prior to study start, and no plans to change medications during the study. This includes long-term -medication like antidepressants, statins, hormones, antihypertensives, or levothyroxine. * Stable exercise routine for a minimum of 3 months prior to study start, with no planned changes to this routine * Stable dietary supplement routine for a minimum of 3 months prior to the study start: includes probiotics, synbiotics, supplemental SCFA's * Willing to receive, set-up, and use all required equipment: the Eight Sleep Pod Cover and Hub, biometric smart ring, urine-based hormone measurement kit, ambulatory blood pressure monitor, core temperature capsule, HST device, and stool collection kits for the required amount of time * Comfortable using research accounts owned by Eight Sleep for some study devices * Willing and able to have stool samples picked up by the research team three and up to five times during the study * Willing to have the research team in the home for study set-up (up to 3 hours) * Have a valid, government issued ID Cohort A specific Inclusion: Postmenopausal women * Assigned female at birth * Postmenopausal: self-reported absence of menstrual period for 12 or more consecutive months prior to study start * No change to hormone replacement therapy (HRT) use within 3 months prior to study start or plans to change HRT status during study period * No changes to hormonal birth control use within 3 months prior to study start or plans to change birth control use during study period Cohort B specific Inclusion: Age-Matched Men -Assigned Male at birth Exclusion Criteria: All Cohorts * Currently taking any of the following medications/supplements or have changed use status (using to not using or vice versa) within 3 months before study start. * Antibiotics (any kind), including one-time or short-term antibiotic use * Corticosteroids (oral or injection only, topical preparations included): * Prednisone * Prednisolone * Dexamethasone * Hydrocortisone * Methylprednisolone (Medrol) * Budesonide * Betamethasone * Anti-TNF-α medications (biologics for arthritis, Crohn's disease, psoriasis, or other immune/inflammatory conditions): * Adalimumab (Humira) * Etanercept (Enbrel) * Infliximab (Remicade) * Certolizumab (Cimzia) * Golimumab (Simponi) * Changed use status (using to not using or vice versa) within 3 months before study start or plans to stop/start the medications during the study. --Statins (cholesterol-lowering medications): * Atorvastatin (Lipitor) * Rosuvastatin (Crestor) * Lovastatin (Mevacor) * Fluvastatin (Lescol) * Antihypertensive drugs (blood pressure medications): * Angiotensoconverting enzyme (ACE) inhibitors: Lisinopril, Ramipril, Perindopril, Enalapril * Angiotensin II receptor blockers (ARBs): Losartan, Valsartan, Candesartan * Calcium channel blockers: Amlodipine (Norvasc), Diltiazem, Verapamil * Beta-blockers: Metoprolol, Atenolol, Bisoprolol, Propranolol * Diuretics: Hydrochlorothiazide, Furosemide (Lasix), Indapamide * Changed use status (using to not using or vice versa) within 3 months before study start or plans to start/stop during the study. * Hormonal birth control (any form): ---Combined oral contraceptives (estrogen + progestin) or progestin-only capsule * Hormonal IUD (e.g. Mirena, Kyleena) * Contraceptive implant (e.g. Nexplanon) * Contraceptive injection (e.g. Depo-Provera) * Contraceptive patch (e.g. Xulane, Evra) * Vaginal ring (e.g. NuvaRing) * Hormone replacement therapy (exceptions: systemic - local vaginal estrogen preparations are not excluded): * Estrogen-based: oral tablets, patches, gel, cream, or vaginal ring * Combined estrogen + progestogen: oral tablets or patches * Progesterone-based: oral tablets or intrauterine device * Testosterone: cream or gel * Bioidentical: oral tablets, patches, gel, cream, pellets, or injections * Currently taking any of the following medications/supplements or have changed use status (using to not using or vice versa) within 3 months before study start or plans to start/stop during the study. --Anabolic-androgenic steroids or performance-enhancing drugs (prescribed or non-prescribed): * Testosterone-based: testosterone enanthate, cypionate, propionate, Sustanon * Synthetic anabolic steroids: nandrolone, stanozolol (Winstrol), oxandrolone (Anavar), methandrostenolone (Dianabol), trenbolone * GLP-1 receptor agonists or other glucose-lowering medications: * GLP-1s: Semaglutide (Ozempic, Wegovy), Liraglutide (Victoza, Saxenda), Dulaglutide (Trulicity), Tirzepatide (Mounjaro, Zepbound) * Other: Metformin (Glucophage), Insulin (all types), Sitagliptin (Januvia), Empagliflozin (Jardiance), Dapagliflozin (Farxiga), Glipizide, Glyburide * Currently taking any of the following medications/supplements or have changed use status (using to not using or vice versa) within 3 months before study start or plans to start/stop taking these drugs during the study period. --Sleep medications: Prescription: Zolpidem (Ambien), Zopiclone (Imovane), Eszopiclone (Lunesta), Temazepam, Nitrazepam, Trazodone (when prescribed for sleep), Suvorexant (Belsomra) Over-the-counter: Diphenhydramine (Benadryl, ZzzQuil, Unisom), Doxylamine (Unisom SleepTabs, Nytol), --Benzodiazepines (use status change within 12 months before study start): Diazepam (Valium), Lorazepam (Ativan), Clonazepam (Klonopin), Temazepam, Nitrazepam * Antidepressant medications (change within 3 months of study start or plans to start/stop taking during the study period) * Stimulants affecting blood pressure: * Methylphenidate (Ritalin, Concerta) * Amphetamine/Dextroamphetamine (Adderall) * Lisdexamfetamine (Vyvanse) * Modafinil (Provigil) * Pseudoephedrine (Sudafed, including other cold/decongestant medications) * Antipsychotics: Quetiapine (Seroquel), Olanzapine (Zyprexa), Risperidone * Mood stabilizers: Lithium, Valproate (Depakote) * Changed use status (using to not using or vice versa) within 3 months before study start or during the study. --CBT-I or pharmacological treatment for insomnia disorder * Changed use status (started or stopped using) within 3 months before study start. * Probiotics, prebiotics, or synbiotics * SCFAs * Butyrate (Sodium butyrate, Calcium/magnesium butyrate, Tributyrin), Acetate, Propionate * Multivitamins containing any of the following minerals: * Iron, Selenium, Calcium, Zinc, Phosphorus, Magnesium Note: Stable long-term multivitamin use (unchanged for ≥3 months) is not excluded Folic Acid, Vitamin C, Vitamin A, Vitamin D, or Vitamin E supplements * Antioxidant supplements * Omega-3 / fish oil supplements * Melatonin (current use excluded if unwilling to cease use during study participation) * Current, ongoing, or history of diagnosis or changed diagnosis status (new diagnosis, revised or reversed diagnosis) within the specified timeframe. * Metabolic Conditions * Diabetes mellitus: Type 1 * Type 2 diabetes (within the past 3 years) * Diagnosed prediabetes (confirmed via Preparation Period hbA1c levels. A result between 5.7-6.4% warrants exclusion from the study) * Chronic hepatitis B/C * Liver cirrhosis * Alcoholic liver disease * Non-alcoholic fatty liver disease (NAFLD) or non-alcoholic steatohepatitis (NASH) (within the past 3 years) * Hepatitis A (within the past 3 years) * Hypothyroidism or hyperthyroidism (including Hashimoto's thyroiditis) * Cardiovascular Conditions * Hypertension * Cardiovascular disease, including: * Coronary artery disease (CAD) or ischemic heart disease * History of myocardial infarction (heart attack) * Heart failure (any grade) * Atherosclerosis * History of stroke or transient ischemic attack (TIA) * Peripheral arterial disease (PAD) * Atrial fibrillation or other major cardiac arrhythmias * Vasovagal syncope: common fainting episode caused by a sudden drop in blood pressure and heart rate * Severe anemia or significant white blood cell or platelet abnormalities * Surgery, severe skin disease, or fistula on the upper arm (interfering with BP cuff readings; within 3 months prior to the study start) * Autoimmune Conditions * Rheumatoid arthritis * Ankylosing spondylitis * Lupus erythematosus * Multiple sclerosis (MS) * Any other diagnosed autoimmune condition or current use of immunosuppressive medications * Gastrointestinal Conditions * Inflammatory bowel disease (IBD), Crohn's disease or ulcerative colitis * Irritable bowel syndrome (IBS) * Celiac disease * Gastroparesis or diverticular disease * History of colostomy, colon cancer, or other colon-related surgeries * Recent gastrointestinal surgery (within 6 months prior to enrollment) * Chronic Diseases * Renal disease (chronic kidney disease, any stage) * Hepatic disease (beyond those listed under metabolic conditions above) * Respiratory or chronic lung disease * Neurological and Psychological Conditions * Dementia * Alzheimer's disease * Parkinson's disease * Schizophrenia * Sleep-Related Conditions * Obstructive sleep apnea (OSA) * Central sleep apnea * Complex sleep apnea syndrome * Narcolepsy or hypersomnia disorders * Restless legs syndrome (RLS) / Willis-Ekbom disease * Periodic limb movement disorder (PLMD) * Circadian rhythm sleep-wake disorders: shift work disorder (SWD), irregular sleep-wake rhythm disorder (ISWRD), or non-24-hour sleep-wake disorder (N24SWD) Note: Participants with delayed sleep-wake phase disorder (DSWPD) or advanced sleep-wake phase disorder (ASWPD) with chronically stable sleep timing may be included. * Participants will be excluded if they participate in any of the following behaviors or conditions within the indicated timeframe. * Substance Use * Current addiction to opiates * Excessive alcohol consumption (more than 14 standard drinks per average 1 week) * Habitual caffeine consumption exceeding 400 mg per day (approximately 4 standard cups of coffee or equivalent) * Recreational frequent drug use within timeframes noted prior to study start: * Cannabis / marijuana (including edibles and oils): daily or near-daily use (defined as ≥5 days per week) within 3 months prior to study start * Cocaine: any use within 3 months prior to study start * MDMA / ecstasy: any use within 3 months prior to study start * Hallucinogens (LSD, psilocybin): any use within 4 weeks prior to study start * Ketamine or other illicit substances: any use within 3 months prior to study start * Diet and Weight * Planning significant changes to diet or lifestyle in the 3 months prior to study start, or had significant changes to diet or lifestyle in the 3 months prior to study start * Starting or stopping a specialized diet (ketogenic, vegan, carnivore, elimination, intermittent fasting) * Significant increase or decrease in exercise load or training plan (change of ≥60 minutes per week in total exercise volume, starting or stopping a structured exercise program, or injury/illness-related activity restriction) within 3 months prior to study start * Currently enrolled in an active weight-loss program, bariatric program, or medically supervised diet, or planning to start one during the study * Weight loss or gain within the past 1 month of 5% of body weight or greater,, or weight loss or gain within the past 6 months of 10% body weight or greater * Health Status at Enrollment ---Acute illness or active infection at the time of recruitment or study start: includes colds, prolonged cough, fevers, etc. * Active cancer diagnosis or receipt of chemotherapy or radiotherapy within 12 months prior to study start, or planned chemotherapy treatment during the study duration * Hospitalization of greater than 24 hours for acute illness, major surgery, sepsis, or cardiac, pulmonary or neurological events within 6 months prior to study start * Study Equipment Compatibility * Unable or unwilling to swallow a standard-sized capsule (required for internal core temperature monitoring capsule) * Currently using a pacemaker or other electromagnetic medical implant (contraindicated with core temperature capsule) * MRI scheduled during the study period or within 1 week after study conclusion * Have or may have a CT scan planned during the study period * Allergic to nickel or aluminum * Sample and Data Collection ---Unable or unwilling to ----Collect and provide at least 3, and up to 5, stool samples ----Store self-collected stool samples in a home freezer until shipment/pick-up (up to 1 week after collection) ----Complete 3 blood panels (3-4 tubes of blood each), including strong aversion to needles ----Complete required digital surveys and any requested data sharing * Communicate with the research team within a timely manner throughout the duration of the study * Have stool samples picked up from home * Have research staff within home for study set-up for up to 3 hours * Complete all data collection requirements in a timely manner * Lifestyle and Compliance * Travel planned during the study period * Unstable WiFi connection at any point during the study period (to the best ability this can be predicted) * Unwilling or unable to provide informed consent with sufficient mental wellness to understand the study * Lived outside of the United States within 6 months prior to study start Cohort A Exclusion Criteria: Postmenopausal women * Hysterectomy * Oophorectomy (single or double) * Polyendocrine metabolic ovarian syndrome (PMOS), previously known as polycystic ovarian syndrome (PCOS) * Diagnosed testosterone dysregulation (hyperandrogenism or androgen insufficiency) not attributable to PMOS * Premature ovarian insufficiency (POI) or premature ovarian failure (POF) * Endometriosis * Change to hormone replacement therapy (HRT) use within 3 months prior to study start * Changes to hormonal birth control use within 3 months prior to study start Cohort B Exclusion Criteria: Age-Matched Men -Diagnosed testosterone dysregulation (hyperandrogenism and/or androgen insufficiency)