The Fatigue Puzzle: 5 Body Systems That Commonly Drain Your Energy

By Andrew Wong, MD, IFMCP

Capital Integrative Health

. https://cihealth.org/

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The Fatigue Puzzle: 5 Body Systems That Commonly Drain Your Energy

1) Sleep: Your Daily Reset

Poor or fragmented sleep heightens inflammation and disrupts hormones that steer thyroid function and blood sugar, so it’s often the first domino. Aim for 7–9 consistent hours, keep a one-week sleep diary (bed/wake times, awakenings), and note red flags like loud snoring, gasping, or needing caffeine to feel functional by mid-morning. If non-restorative sleep or snoring is persistent, ask about a home sleep study to evaluate for sleep apnea—treating it can markedly improve daytime energy and metabolic balance.

2) Thyroid: The Metabolic Thermostat

When thyroid output is low, cells make less energy, and fatigue pairs with feeling unusually cold, weight changes, dry skin, hair thinning, or slowed bowels. Because sleep loss and inflammation can skew thyroid signals, track symptoms alongside your sleep diary. If several signs fit, request TSH with reflex free T4; based on your history, your clinician may add TPO antibodies and sometimes free T3 to clarify the picture and guide treatment.

3) Iron Status: Oxygen Delivery

Iron is essential for carrying oxygen to tissues; even without overt anemia, low iron stores can sap stamina, focus, and exercise tolerance. Watch for brittle nails, frequent headaches, shortness of breath on routine exertion, or restless legs—especially if periods are heavy or you follow a low-iron diet. Instead of guessing with supplements, ask for ferritin, a complete blood count, and iron studies (serum iron, TIBC, transferrin saturation) so dosing can be safe and targeted.

4) Blood Sugar: Peaks and Crashes

Big glucose swings can cause afternoon slumps and brain fog, and poor sleep makes those swings more likely. Notice whether you feel shaky, hungry, or foggy 1–3 hours after a high-carb meal. For a simple trial, lead meals with protein and fiber for a week and see if energy stabilizes. If fatigue persists or risk factors are present, ask for fasting glucose and A1C; some people benefit from fasting insulin or a clinician-guided glucose log to spot patterns.

5) Chronic Inflammation: The Background Noise

Smoldering inflammation diverts resources, disturbs sleep, and worsens insulin resistance, keeping you tired. Clues include morning stiffness over 30 minutes, bleeding gums, irritable bowels, or lingering post-viral symptoms. Because sources vary—from periodontal disease to autoimmune issues—screening may include hs-CRP and ESR, followed by targeted evaluation based on your story and exam.

Pulling these threads together is powerful: stabilize sleep and meals, walk daily, hydrate, and record what changes your energy. If fatigue persists, bring your notes to a clinician and request focused labs from the areas above. The right tests turn guesswork into a plan—and help you get your energy back.