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.
- 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.
- 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)