Higher Daily Step Count Predicts Very Slightly Higher Body Mass Index Or BMI for Population

Body Mass Index Or BMI was generally 1% higher than average after a total of 8870 count of Daily Step Count over the previous 7 days.

Aggregated data from 134 study participants suggests with a HIGH degree of confidence (p=0.147, 95% CI -0.173 to 0.186) that Daily Step Count has a very weakly positive predictive relationship (R=0.0068) with Body Mass Index Or BMI.

The highest quartile of Body Mass Index Or BMI measurements were observed following an average 144 count Daily Step Count per day.

The lowest quartile of Body Mass Index Or BMI measurements were observed following an average 7190 count of Daily Step Count per day.

After an onset delay of 0 seconds, Body Mass Index Or BMI is typically 1% lower than average over the 7 days following around 7190 count Daily Step Count.

The objective of this study is to determine the nature of the relationship (if any) between Daily Step Count and Body Mass Index Or BMI. Additionally, we attempt to determine the Daily Step Count values most likely to produce optimal Body Mass Index Or BMI values.

Manual Recording Option

Create a reminder for Steps here and record it daily by enabling notifications or using the reminder inbox here .

Manual Recording Option

Create a reminder for Body Mass Index or BMI here and record it daily by enabling notifications or using the reminder inbox here .

This study is based on data donated by 134 participants. Thus, the study design is equivalent to the aggregation of 134 separate n=1 observational natural experiments.

Steps Pre-Processing

Steps measurement values below 1 count were assumed erroneous and removed. No maximum allowed measurement value was defined for Steps. No missing data filling value was defined for Steps so any gaps in data were just not analyzed instead of assuming zero values for those times.

Body Mass Index or BMI Pre-Processing

Body Mass Index or BMI measurement values below 0 index were assumed erroneous and removed. Body Mass Index or BMI measurement values above 100 index were assumed erroneous and removed. No missing data filling value was defined for Body Mass Index or BMI so any gaps in data were just not analyzed instead of assuming zero values for those times.

Predictive Analytics

It was assumed that 0 seconds would pass before a change in Daily Step Count would produce an observable change in Body Mass Index Or BMI.

It was assumed that Daily Step Count could produce an observable change in Body Mass Index Or BMI for as much as 7 days after the stimulus event.

Using a two-tailed t-test with alpha = 0.05, it was determined that the change in Body Mass Index Or BMI is statistically significant at 95% confidence interval.

After treatment, a 0.1% decrease (0.0914 index) from the mean baseline 27.1 index was observed. The relative standard deviation at baseline was 2.85448%. The observed change was 0.623952 times the standard deviation.

A common rule of thumb considers a change greater than twice the baseline standard deviation on two separate pre-post experiments may be considered significant. This occurrence would have only a 5% likelihood of resulting from random fluctuation (a p-value < 0.05).

Daily Step Count data was primarily collected using Fitbit. Fitbit makes activity tracking easy and automatic.

Body Mass Index Or BMI data was primarily collected using Fitbit. Fitbit makes activity tracking easy and automatic.

As with any human experiment, it was impossible to control for all potentially confounding variables. Correlation does not necessarily imply causation. We can never know for sure if one factor is definitely the cause of an outcome. However, lack of correlation definitely implies the lack of a causal relationship. Hence, we can with great confidence rule out non-existent relationships. For instance, if we discover no relationship between mood and an antidepressant this information is just as or even more valuable than the discovery that there is a relationship.

We can also take advantage of several characteristics of time series data from many subjects to infer the likelihood of a causal relationship if we do find a correlational relationship. The criteria for causation are a group of minimal conditions necessary to provide adequate evidence of a causal relationship between an incidence and a possible consequence.

Criteria For Causal Inference

Strength (A.K.A. Effect Size)

A small association does not mean that there is not a causal effect, though the larger the association, the more likely that it is causal. There is a very weakly positive (R = 0.0068) relationship between Daily Step Count and Body Mass Index Or BMI.

Consistency (A.K.A. Reproducibility)

Consistent findings observed by different persons in different places with different samples strengthens the likelihood of an effect. Furthermore, in accordance with the law of large numbers (LLN), the predictive power and accuracy of these results will continually grow over time. 51879 paired data points were used in this analysis. Assuming that the relationship is merely coincidental, as the participant independently modifies their Daily Step Count values, the observed strength of the relationship will decline until it is below the threshold of significance. To it another way, in the case that we do find a spurious correlation, suggesting that banana intake improves mood for instance, one will likely increase their banana intake. Due to the fact that this correlation is spurious, it is unlikely that you will see a continued and persistent corresponding increase in mood. So over time, the spurious correlation will naturally dissipate.

Specificity

Causation is likely if a very specific population at a specific site and disease with no other likely explanation. The more specific an association between a factor and an effect is, the bigger the probability of a causal relationship.

Temporality

The effect has to occur after the cause (and if there is an expected delay between the cause and expected effect, then the effect must occur after that delay). The confidence in a causal relationship is bolstered by the fact that time-precedence was taken into account in all calculations.

Biological Gradient

Greater exposure should generally lead to greater incidence of the effect. However, in some cases, the mere presence of the factor can trigger the effect. In other cases, an inverse proportion is observed: greater exposure leads to lower incidence.

Plausibility

A plausible bio-chemical mechanism between cause and effect is critical. This is where human brains excel.

Based on our responses so far,

0 humans feel that there is a plausible mechanism of action for a relationship between Daily Step Count and Body Mass Index Or BMI.

0 humans feel that any relationship observed between Daily Step Count and Body Mass Index Or BMI is coincidental.

Coherence

Coherence between epidemiological and laboratory findings increases the likelihood of an effect. It will be very enlightening to aggregate this data with the data from other participants with similar genetic, diseasomic, environmentomic, and demographic profiles.

Experiment

All of human life can be considered a natural experiment. Occasionally, it is possible to appeal to experimental evidence.

Analogy

The effect of similar factors may be considered.

A plausible bio-chemical mechanism between cause and effect is critical. This is where human brains excel. Based on our responses so far, 0 humans feel that there is a plausible mechanism of action and 0 feel that any relationship observed between Daily Step Count and Body Mass Index Or BMI is coincidental.