Does Alcohol Thin Your Blood?

Heavy drinking is connected to illnesses that lead to poor health, including heart conditions. Excessive alcohol consumption can lead to high blood pressure, heart failure, or stroke. Alcohol can interfere with the clotting process by making platelets less sticky and reducing the ability to form stable blood clots.

Differences between protocol and review

Doing this can increase the risk of severe bleeding due to an accident or injury. Understanding the effects of alcohol on blood is crucial in dispelling misconceptions and promoting accurate information. By shedding light on the immediate and long-term effects of alcohol on blood, we can better understand the implications of alcohol consumption on overall health and well-being.

• It’s essential to differentiate between the effects of alcohol on blood flow and the actual thickness of the blood.
• This may lower your risk for the type of strokes caused by blockages in blood vessels.
• It’s important to note that the effects of alcohol on blood can vary depending on various factors, such as the amount and frequency of alcohol consumption, overall health, and individual differences.
• We also checked the lists of references in the included studies and articles that cited the included studies in Google Scholar to identify relevant articles.
• Of the 32 included studies, seven studies used a manual mercury sphygmomanometer or a semi‐automated sphygmomanometer for BP measurement (Bau 2005; Dai 2002; Karatzi 2005; Kojima 1993; Potter 1986; Rossinen 1997; Van De Borne 1997).

Beilin 1992 published data only

• If you’re a regular drinker, you may need to get your medication levels checked more often.
• Many interrelated changes are possibly responsible for the biphasic effect of alcohol on blood pressure.
• Ultimately, it is up to you to make the right decision for your health and wellbeing.
• In small amounts, alcohol can act as an anticoagulant, reducing blood’s ability to clot and causing it to start thinning.
• You should ask your healthcare provider if you shouldn’t take anticoagulants because of any other medications you take or conditions you have.

This antioxidant may reduce harmful cholesterol levels and minimize the risk of blood clots. In small amounts, alcohol can act as an anticoagulant, reducing blood’s ability to clot and causing it to start thinning. For moderate drinkers, the blood-thinning effects of alcohol are short-lived. Alcohol leaves the bloodstream at an average rate of about 0.015 g per hour. Blood cells, called platelets, move to the injured area of the body when you’re cut or bruised.

Description of studies

Liver disease can affect the production of proteins necessary for blood clotting. Consequently, it can lead to an imbalance in the clotting process, increasing the risk of bleeding disorders. Depending on the amount consumed, alcohol can either increase or decrease blood pressure. Moderate alcohol consumption may lead to a slight decrease in blood pressure, while excessive alcohol intake can cause a significant rise in blood pressure. For medium doses of alcohol, moderate‐certainty evidence shows a decrease in SBP and DBP six hours after alcohol consumption, and low‐certainty evidence suggests a decrease in SBP and DBP for 7 to 12 hours after alcohol consumption.

A blood clot can form anywhere in your body and if it ruptures, the pieces can travel to other blood vessels and cause life-threatening conditions, such as pulmonary embolism, stroke, or heart attack. Alcohol can increase blood pressure, damage your heart, cause strokes, and has an unpredictable blood-thinning effect that you can’t rely on. Sara Tasnim (ST) and Chantel Tang (CT) drafted the protocol with help from JMW. Both ST and CT independently assessed studies for inclusion or exclusion and assessed the risk of bias of all included studies. We identified Stott 1987 and Barden 2013 from Analysis 3.1 and Analysis 3.2 as having a considerably lower standard error (SE) of the mean difference (MD) compared to the other included studies. Assuming that the low SEs of MDs reported in Stott 1987 and Barden 2013 are errors and are not reliable, we replaced these measures with the average SE of MD from the rest of the included studies.

References to studies excluded from this review

These contrasting effects underscore the need for balanced alcohol consumption and awareness of individual health factors. Further research is necessary to fully elucidate the mechanisms behind alcohol’s impact does alcohol thin your blood effects and impact on blood viscosity and to develop guidelines that maximize potential benefits while minimizing risks. As with many aspects of health, moderation remains key when considering the role of alcohol in cardiovascular well-being. The dose of alcohol had to be reported by study authors for inclusion in the systematic review.

This causes a temporary expansion of the blood vessels, leading to a feeling of warmth and potentially causing the skin to appear flushed. Additionally, the authors discussed older studies that suggested binge drinking can cause temporary increases in blood pressure. They also highlighted that long-term heavy drinking and binge drinking may increase someone’s risk of various cardiovascular conditions.

However, it’s important to note that this is a misconception and does not reflect the true nature of blood thickness. However, the researchers also warned that they do not recommend drinking alcohol to reduce the risk of heart conditions because alcohol harms your health. A study published in 2023 reports that the stress-lowering effect of light alcohol consumption (no more than one drink daily for women and two for men) lowers your risk of cardiovascular disease.

The evidence synthesised in this review was collected from 32 RCTs in 767 participants. Of the 32 studies, two studied low‐dose alcohol, 12 studied medium‐dose alcohol, and 19 studied high‐dose alcohol. The sample size in the meta‐analysis for low‐dose comparison was not adequate to assess the effects of low doses of alcohol on BP and HR; however, we believe that the direction of the change in BP and HR was correct. For medium doses and high doses of alcohol, participants represented a range in terms of age, sex, and health condition. Because the participant population comprised predominantly young and healthy normotensive men, the overall evidence generated in this review cannot be extrapolated to women and older populations with other comorbidities. Low‐dose alcohol consumption had no effect on blood pressure (BP) within six hours, but we found only two trials that studied this dose and no trials that assessed BP after six hours.

Kawano 1992.

In the United States, 14 grams of pure alcohol is considered as one standard drink or one unit, and the maximum daily limit for men and women is four and three drinks, respectively (NIAAA 2017). Exceeding this limit increases the risk of cardiovascular, hepatic, and nervous system disorders (Bellentani 1997; Fuchs 2001; Gao 2011; Lieber 1998; McCullough 2011; Nutt 1999; Welch 2011). Also, multiple studies have found associations between consumption of alcoholic beverages and specific cancers (Kushi 2012; Seitz 2007). Abuse of alcohol resulted in approximately 3 million deaths worldwide and 132.6 million disability‐adjusted life years (DALYs) in 2016 (WHO 2018).

The study author explained the blinding method in detail in an email, so we classified this study as having low risk of bias. We used GRADEpro software to construct a ‘Summary of findings’ table to compare outcomes including change in SBP and DBP and HR (GRADEpro 2014). In addition, we included illustrative risks to present findings for the most important outcome (change in systolic blood pressure). All randomised controlled trials (RCTs) that compared alcohol to placebo or similar tasting non‐alcoholic beverages were included in this systematic review.

Based on nine RCTs in which participants consumed alcohol repeatedly over days, these review authors reported that alcohol increases SBP by 2.7 mmHg and DBP by 1.4 mmHg. However, they excluded studies for which the duration of BP observation was less than 24 hours and articles published in non‐English languages. We believe that inclusion of those studies will provide useful information about the dose‐related magnitude and time‐course effect of alcohol on blood pressure in people with both normal and elevated blood pressure. One of the primary effects of alcohol on blood clotting is its ability to interfere with the function of platelets. Alcohol can make platelets less sticky, resulting in a reduced ability to form a stable blood clot.

Frisk‐Holmberg 1990 published data only

In Barden 2013, treatment allocation was performed by a statistician who was not involved in the trial. Opaque sealed randomised envelopes were used in Cheyne 2004 and Foppa 2002, and random number allocator was used in Rosito 1999. It is important to note that information regarding the method of allocation concealment used in Foppa 2002 and Rosito 1999 was provided by the study author via email. We also contacted Hering 2011, but the study author did not explicitly mention in the email the method of allocation concealment used.