There has been an increased interest in participating in sober curious challenges, such as Sober October and Dry January—worldwide initiatives in which people commit to being alcohol-free for the entirety of that month. Some people enter these challenges wanting to take control of their health or as a way to reevaluate their relationship with alcohol. Depending on the frequency of alcohol consumption, the pattern of use over time, and even the type of alcohol consumed, there is evidence that some alcohol consumption may benefit health. However, there is substantial evidence linking long-term excessive drinking to a variety of health problems. 
Some research even shows that a month-long hiatus from alcohol improves feelings of well-being, like sleeping more soundly and having more energy.  But, little is known about the clinical significance of the reduction of total drinks or temporary abstinence to reduce overall intake, especially as it relates to an extensive bloodwork panel. 
InsideTracker's first clinical trial—the Inside Impact: Sober October Study—takes a novel approach to answer the question,
How does abstaining from alcohol for 31 days impact lifestyle factors, objective blood biomarkers, and physiomarkers like sleep and heart rate in healthy, moderate drinkers?
Study investigators hypothesized that at least half of the participants would report an improvement in at least one lifestyle-related factor, like stress or sleep. Not only was that hypothesis upheld, but there were significant changes in several biomarkers at the end of the trial.
Read on to learn more about the trial and the impact of Sober October on markers of health.
The Inside Impact: Sober October Study
In total, 30 participants who were all InsideTracker customers were enrolled in the trial. These individuals were all of the legal drinking age in the United States—21 years—and consumed 1-14 drinks a week. During the study, they agreed to:
- Refrain from all alcohol use for the 31 days of the study
- Complete an InsideTracker Ultimate Plan blood test 3-5 days before the start of the abstinence period and on day 31, or the final day of the study, prior to consuming any alcohol
- Provide InsideTracker access to the test data
At the time of the study, The Ultimate Plan included an analysis of 43 blood biomarkers. Participants completed their second Ultimate Plan before resuming alcohol consumption and completed a post-study survey reporting subjective lifestyle data and adherence to the alcohol-free protocol. In total, 28 participants self-reported that they abstained from alcohol for the duration of the study period (93%). Group average biomarker and physiomarker values were assessed at baseline and follow-up and compared.
What did the results of the study show?
InsideTracker's data science team analyzed the data from the self-reported lifestyle factors survey, blood biomarker analysis, and physiomarker metrics obtained from fitness trackers. A t-test was used to compare study participants' biomarker and physiomarker levels at both the start and end of the study. Statistical significance was determined at (p≤0.05). Here are a few of the highlights:
Subjective lifestyle factors
The Inside Impact: Sober October Study met its primary endpoint—greater than 50% of study participants exhibited an improvement in one or more of the following characteristics as self-assessed by survey completion:
- Sleep quality/duration
- Athletic performance
- Post-exercise recovery
- Energy level
- Hydration level
These findings are consistent with current literature on the impact of alcohol cessation on health. 
As a group, participants saw significantly decreased HDL cholesterol levels (-9%), and these findings remained significant in the compliant group (-9%), females (-7%), and males (-14%).
This finding is consistent with previous studies, which show that moderate alcohol consumption is associated with increased HDL cholesterol levels.  Previous studies also suggest that alcohol abstention is associated with decreased HDL cholesterol levels. [6,7]
“The relationship between HDL and alcohol is well established. And the fact that alcohol abstention decreased HDL values in our study population was an encouraging positive control for us to see and provides additional confidence in the other statistically significant findings,” says Dr. Renee Deehan, Vice President of Science and Artificial Intelligence and InsideTracker and the study’s principal investigator.
Neutrophils to lymphocyte ratio
Results showed a significantly decreased neutrophils (-11%) and increased lymphocyte counts (+9%), and these findings remained significant in the compliant group, neutrophils (-12%) and lymphocytes (+9%). However, the findings were not significant when data were broken down by sex.
The ratio of neutrophils to lymphocytes (NLR) is commonly used as a way to evaluate the balance between systemic inflammation (neutrophil count) and adaptive (longer-term) immunity (lymphocyte count). In the general population, increased NLR is associated with overall mortality and mortality due to heart disease, lower respiratory disease, influenza and pneumonia, and kidney disease. [8-10]
“Based on findings in this study and current cross-sectional data, InsideTracker’s science team is currently conducting a literature search to understand the potential to bring insights on NLR to InsideTracker’s product,” says Michelle Cawley, MS, InsideTracker’s Science Team Manager.
The study also assessed the impact of alcohol abstention on physiological changes captured by wearable devices (including Garmin smartwatches, Fitbit, and Apple Watch) in 22 of the 30 participants. A preliminary analysis showed statistically significant changes in the resting heart rate (RHR) of participants—seven-day average RHR moved from 57.5 bpm to 55.5 bpm—a 3.5% reduction (p=0.003). This finding is consistent with current literature, which reports that alcohol consumption is associated with increased RHR. 
Changes in sleep duration and sleep efficiency were assessed and findings were not statistically significant.
Keep this in mind about the study
As with every scientific study, there are limitations to the Inside Impact: Sober October Study’s findings. The sample size of 30 participants was relatively small, and the study duration was relatively short. Information such as the type of alcohol participants typically consumed was not collected. In addition, factors such as changes in nutrition, genetics, medication use, and medical conditions can impact blood biomarker levels and were not collected from study participants. Preliminary analyses were not adjusted for factors associated with biomarker levels, for example, age, social determinants of health, and BMI. Statistical analysis was conducted at the group level only; variations may differ at the individual level.
What does this mean for you?
If you participate in alcohol-free challenges like Sober October and Dry January, you may experience both subjective changes like improvements in sleep quality, as well as objective changes like shifts in blood biomarker levels. And while there isn’t a one-size-fits-all recommendation as to whether consuming or abstaining from alcohol is right for you, tracking your subjective lifestyle factors and leveraging blood analysis can help you to understand its impact on your health.
Stay tuned for further analyses on the Inside Impact: Sober October Study from InsideTracker’s scientists. “This is just the beginning, InsideTracker is committed to the continuation of rigorous, ethical clinical research in the healthspan space,” notes Dr. Deehan.
Michelle Darian, MS, MPH, RDMichelle is a Nutrition Specialist at InsideTracker. As a Registered Dietitian, you’ll find Michelle analyzing the research behind recent nutrition trends, bringing actionable food and supplement recommendations to the platform. When she's not myth-busting, Michelle can be found exploring new restaurants and getting creative in her kitchen.