How the Holidays Affect Your Blood and Health: What Biomarkers Reveal

Every year, the holiday season brings joy, celebration, and plenty of indulgence. Family gatherings, festive meals, sweet treats, late-night parties, and a few extra glasses of wine often feel like traditions we can’t imagine skipping. Most of us expect that the holidays might leave us with a few extra pounds or a tighter waistband. But what if the impact goes much deeper than that? What if the holidays literally change your blood?

The truth is, the lifestyle shifts that happen during this time—what we eat, how much we drink, how late we stay up, how stressed we get, and how little we move—can all be detected in our bloodwork. Your blood is like a diary of your recent habits, quietly recording changes in sugar, fat, liver function, inflammation, and even hormones. Understanding these changes doesn’t just help us make sense of why we feel sluggish after the holidays; it can also give us valuable insight into our long-term health.

In this article, we’ll explore how the holidays impact your blood biomarkers, why it matters, and what you can do to enjoy the season without putting your health at unnecessary risk.

What Are Blood Biomarkers and Why They Matter

To understand how the holidays influence your health, it helps to first know what a biomarker is. A biomarker is simply a measurable indicator of something happening in your body. Doctors and scientists use biomarkers to check how organs are working, to diagnose diseases, and to monitor progress over time.

For example, your blood sugar is a biomarker that shows how well your body processes carbohydrates. Cholesterol is a biomarker that reveals how fats are circulating in your bloodstream. Inflammation markers like C-reactive protein (CRP) give a window into how stressed or inflamed your body might be. Hormones such as cortisol or testosterone are also biomarkers, since they reflect how your body is responding to stress, sleep, and other factors.

When you get a standard blood test at your doctor’s office, you’re essentially getting a snapshot of these biomarkers. The results can show whether your body is in balance or whether something is out of range. What’s fascinating is that these numbers don’t just change in the long term—they can shift quickly in response to short-term changes in lifestyle. That means a week or two of holiday indulgence can temporarily alter your blood profile in noticeable ways.

The Holiday Lifestyle Shift: What Really Changes

The holidays are not just another time of year—they represent a dramatic lifestyle shift for many people. Our usual patterns of eating, sleeping, and moving often get disrupted. Instead of balanced meals, we eat heavier foods rich in sugar, salt, and fat. Instead of going to bed on time, we stay up late at parties or wake up early to travel. Instead of exercising regularly, we might skip workouts altogether. And instead of calm, we often deal with more stress—whether from gift shopping, family tensions, or year-end work deadlines.

These changes may feel temporary, but your body notices them almost immediately. Food and drink choices directly affect blood sugar, cholesterol, and triglycerides. Alcohol puts extra strain on the liver, showing up in liver enzyme levels. Stress hormones rise with family or financial pressures, while sleep disruption can throw hormones and inflammation out of balance. Even hydration takes a hit, as alcohol and salty foods can leave you more dehydrated than usual.

Put together, these small daily shifts create a ripple effect that shows up in your bloodwork.

Key Biomarkers the Holidays Affect

Blood Sugar (Glucose and HbA1c)

One of the most obvious changes during the holidays is blood sugar. With endless trays of cookies, pies, chocolate, and holiday drinks, sugar intake skyrockets. Eating large amounts of refined carbohydrates and sweets causes spikes in glucose, which your body works hard to bring back down. If you do this repeatedly, your average blood sugar levels rise, and markers like HbA1c—which reflects blood sugar control over the past three months—may tick upward.

These spikes can make you feel sluggish, tired, or irritable, especially after big meals. For people already at risk of prediabetes or diabetes, holiday eating can push blood sugar to concerning levels. Even in healthy people, temporary spikes can contribute to oxidative stress and inflammation.

Lipids (Cholesterol and Triglycerides)

Holiday meals often include rich meats, creamy sauces, fried foods, and lots of desserts—all of which can raise cholesterol and triglyceride levels in the blood. Triglycerides, in particular, can jump significantly after a season of indulgence, because they respond quickly to high-fat, high-sugar meals.

Elevated cholesterol and triglycerides don’t usually cause immediate symptoms, but they’re closely tied to heart disease risk over time. Even a few weeks of higher levels may not cause lasting harm if you return to healthy habits, but repeated yearly spikes can contribute to cumulative damage.

Liver Enzymes (ALT, AST, GGT)

Alcohol is one of the biggest holiday culprits for blood changes. Drinking more than usual stresses the liver, the organ responsible for filtering toxins and metabolizing alcohol. This often shows up in elevated liver enzymes such as ALT, AST, and GGT. These markers can increase after just a few nights of heavy drinking and may take weeks to normalize.

While the liver is resilient, repeated strain—year after year—can lead to longer-term issues like fatty liver disease.

Inflammatory Markers (CRP)

Inflammation is another hidden consequence of holiday habits. Stress, poor sleep, sugary foods, alcohol, and lack of exercise all fuel inflammation in the body. This can show up in blood tests as higher C-reactive protein (CRP). Inflammation doesn’t just make you feel achy or tired—it’s also a risk factor for heart disease, autoimmune conditions, and other chronic illnesses.

Hormones (Cortisol, Testosterone, Estradiol)

Holiday stress can increase cortisol, the body’s main stress hormone. Higher cortisol can make you feel anxious, disrupt sleep, and even lead to higher blood sugar. Meanwhile, disrupted routines can also affect sex hormones like testosterone and estradiol, which are sensitive to changes in sleep, alcohol intake, and stress. These shifts might not cause immediate harm but can affect mood, energy, and overall well-being.

Hydration and Kidney Markers (Creatinine, BUN)

Alcohol and salty foods can leave you dehydrated, which may be reflected in markers like blood urea nitrogen (BUN) and creatinine. Dehydration can also contribute to fatigue, headaches, and dizziness, making the holiday “hangover” worse.

How Long Do These Changes Last?

The good news is that for most people, holiday-related blood changes are temporary. Blood sugar spikes usually normalize within days if you return to balanced eating. Triglycerides and cholesterol can come down within weeks of healthier eating and regular exercise. Liver enzymes may take a bit longer—sometimes a month or more—depending on alcohol intake and overall liver health. Inflammation and stress hormones also tend to settle once routines stabilize and stress decreases.

That said, if every holiday season brings weeks of poor habits, the cumulative effect adds up. What seems temporary each year can eventually tip into long-term health problems. That’s why paying attention to these patterns matters—it’s not about guilt, but about awareness.

Holiday Bloodwork: Should You Test Before or After?

If you plan to get bloodwork done around the holidays, timing matters. If you want the most accurate picture of your baseline health, it’s best to schedule your blood test before the holidays begin. That way, your results won’t be skewed by a week of heavy eating or drinking.

On the other hand, testing after the holidays can still be useful. It can show you how your habits affect your biomarkers and highlight areas that need attention. Just keep in mind that results taken right after a holiday weekend may not reflect your “normal” state. If possible, wait a couple of weeks after returning to your usual routine before testing.

RELATED READ: Normal Blood Sugar Levels by Age: Glucose Charts & What They Mean for Your Health

Practical Tips to Protect Your Blood Health During the Holidays

The goal isn’t to avoid all indulgence—holidays are meant to be enjoyed. Instead, think about balance and small strategies that help minimize the impact on your blood health. Staying hydrated is one of the simplest ways to protect both your liver and kidneys. Eating fiber-rich foods like vegetables and whole grains can help keep blood sugar stable, even if you’re having dessert. Adding some protein to each meal helps too.

Moving your body daily—even just a 20-minute walk after meals—can improve blood sugar and triglycerides. Managing stress with small practices like deep breathing or taking breaks during family gatherings can help lower cortisol and inflammation. Prioritizing sleep, even if imperfect, also makes a huge difference. And if you drink alcohol, pacing yourself, eating while drinking, and alternating with water can reduce strain on the liver.

Big Picture: Why Paying Attention to Holiday Blood Changes Matters

The main reason to understand holiday-related blood changes is not to create fear but to empower you. Your blood is a reflection of your habits, and learning how it responds can help you make smarter choices. The holidays might cause short-term shifts, but these changes become meaningful if repeated year after year. Over time, they can contribute to conditions like diabetes, heart disease, and liver problems.

At the same time, awareness gives you control. By making small adjustments, you can enjoy the holidays fully without leaving your body in worse shape come January. Think of it as an opportunity to learn how resilient your body is—and how much better you feel when you support it.

Conclusion: Your Blood Remembers the Holidays

As the holiday season approaches, it’s worth remembering that what happens in December doesn’t stay in December—it leaves a mark in your blood. Biomarkers like glucose, triglycerides, liver enzymes, and inflammatory markers can all shift in response to holiday habits. While most changes are temporary, they reveal how sensitive our bodies are to lifestyle patterns.

The good news is that your blood also records the positive changes you make. A little balance, some movement, proper hydration, and mindful eating can go a long way toward keeping your blood—and your health—in a good place during the festive season. The holidays are a time to celebrate, but with awareness and a few smart choices, you can step into the new year feeling not just joyful but also healthier.

FAQs

1. Does holiday eating really affect blood test results?

Yes. Even a week of heavy eating and drinking can temporarily raise blood sugar, triglycerides, liver enzymes, and inflammation markers.

2. How long should I wait after the holidays to do a blood test?

For the most accurate results, wait one to two weeks after resuming your normal routine. This gives your biomarkers time to settle back toward baseline.

3. Can one week of overeating really harm my health?

In the short term, most effects are reversible. But repeated yearly spikes can contribute to long-term risks, especially for heart and metabolic health.

4. Why do I feel more tired or inflamed during the holidays?

A combination of high sugar intake, alcohol, poor sleep, stress, and dehydration can all increase inflammation and fatigue.

5. What’s the best way to recover from holiday health habits?

Return to balanced meals with fiber and protein, hydrate well, move daily, and prioritize sleep. Within a couple of weeks, most biomarkers should normalize.