- Lactate shows how hard you are working. It does not show how much energy you have available for it.
- Glucose and β-ketones reveal which store your body is currently drawing on: carbohydrates or fat.
- Uric acid is a trace of hard exercise, lack of fluids and diet. What is meaningful is the trend.
- Total cholesterol is a value for the long view over months, not for the individual training session.
- All the values are a guide for your training. They do not replace a medical examination.
In the step test, lactate takes centre stage, and rightly so. But a lactate value never arises in a vacuum: it depends on what you have eaten, how full your stores are and how well recovered you are. This chapter shows what the four other values of the Metabol Pro say about these conditions and how you can use them for your training.
Why more than lactate?
During any exercise, your body burns a mix of carbohydrates and fat. Lactate is produced when the carbohydrates are broken down. If your carbohydrate stores are well filled, the muscle produces more lactate at the same workload than it does with empty stores. This has a consequence that surprises many people: if you go into a step test with empty stores, you measure lower lactate values. The curve slides to the right, and the thresholds look better than they are.
This is exactly where the other parameters help. They do not show you once again how hard you are working, but under what conditions. This lets you put a lactate value into its proper context and manage your nutrition, your training load and your recovery in a more targeted way.
| Parameter | What it shows | Time horizon |
|---|---|---|
| Lactate | How hard carbohydrate metabolism is being pushed at that moment | Minutes, every stage |
| Glucose | How much carbohydrate fuel is available in the blood | Minutes to hours |
| β-ketones | Whether your body is making greater use of fat as an energy source | Hours to days |
| Uric acid | Traces of hard exercise, lack of fluids and diet | Days |
| Total cholesterol | A general metabolic value | Months |
Glucose: the fuel in your blood
Glucose is sugar in the blood, and for the muscles it is the fastest fuel. The body keeps blood sugar within narrow limits. During long or hard exercise, however, the muscles draw on the stores in muscle and liver, and when these run low, blood sugar can fall. Many athletes know this as “hitting the wall”: the legs grow heavy and concentration fades.
What this means for your training:
- In the step test: Measure glucose before the test and note the value. An unusually low starting value is an indication that your stores were not full. In that case the lactate values should also be read with caution.
- Comparable tests: Eat similarly in the 24 hours before every test, and do not train hard the day before. The glucose values before the test show you whether you managed that.
- Long sessions and race preparation: If you are testing your fuelling for a marathon, a long-distance cycling event or a triathlon, you can measure glucose at intervals along the way. If it stays stable, your carbohydrate intake is more likely to match the effort than if it drops markedly.
β-ketones: when the body switches to fat
When carbohydrates run short, the liver produces what are known as ketone bodies from fat. The most important of these is β-hydroxybutyrate, and this is exactly the value the Metabol Pro measures. Ketones are produced, for example, during fasting, on a very low-carbohydrate diet, during sessions on an empty stomach and towards the end of very long efforts.
What this means for your training:
- Checking your nutrition strategy: Some athletes deliberately use phases with few carbohydrates, such as fasted base endurance sessions. The ketone value shows whether your metabolism is actually responding to this. Without measurement, it remains a guess.
- Scheduling tests sensibly: Elevated ketones together with low glucose mean that your carbohydrate stores are empty. In a phase like this you measure lower lactate values. So do not schedule a step test during a fasting or low-carb phase, or at least document it.
- Understanding long efforts: If ketones rise towards the end of a long session, your body is making greater use of fat. Together with the glucose trend, you can see when your carbohydrate reserves are running low.
Uric acid: a trace of exercise and diet
Uric acid is produced when the body breaks down substances known as purines. Purines are building blocks of cells and are also found in food, especially in meat, offal and some fish. During very hard or very long exercise, the muscle additionally breaks down energy-carrying compounds, and this also produces uric acid. It is excreted via the kidneys.
The uric acid value therefore typically rises after very intense or very long exercise, when you drink too little, during fasting and on a low-carbohydrate diet. In the last two cases, ketones play a part: they are also excreted via the kidneys and, in the process, slow down the excretion of uric acid.
What this means for your training:
- Monitoring hard training blocks: Measure in the morning on an empty stomach, always under the same conditions, and write the values down together with training, sleep and how you feel. If the value is clearly above your personal baseline for several days, that is a reason to review your training load, fluid intake and diet.
- After a race: The trend in the days after a marathon or a hard race shows how your metabolism settles down again.
- Reading it together with ketones: In fasting and low-carb phases, a higher uric acid value is to be expected. It then says more about diet than about training.
Uric acid is not a fatigue gauge that hands you a ready-made verdict. Research on uric acid as a marker of training load is limited. Its value lies in being an additional piece of the puzzle over time, not in a single number.
Total cholesterol: the long view
Cholesterol is a building material that the body needs for cell membranes and hormones. It is carried in the blood in different transport forms, known as HDL and LDL. The Metabol Pro measures total cholesterol, i.e. the sum. It does not distinguish between HDL and LDL.
Regular endurance training has an effect on blood lipids, but slowly: over months and years, not over days. A single training session hardly changes the value.
What this means for your training:
- Measure rarely, but regularly: For example, at the beginning and at the end of a season, in the morning on an empty stomach. Over the years this builds up a trend.
- Use it as a basis for discussion: The trend is a good prompt for your next sports medical examination. There, the blood lipids are determined in full and assessed by a doctor.
Reading the values together
The values are most useful when you combine them. The overview shows which values belong together in which situation.
| Situation | Measure these values | What you take from it |
|---|---|---|
| Step test | Lactate per stage, glucose before the start | Whether the conditions were right for a meaningful test |
| Long base endurance session | Glucose and β-ketones at intervals, lactate as spot checks | Whether the pace really was easy and when carbohydrates run short |
| Testing your fuelling | Glucose over time | Whether your carbohydrate intake matches the effort |
| Low-carb or fasting phase | β-ketones, glucose, uric acid | Whether the diet is having an effect, and why lactate values are lower now |
| Hard training block, race | Uric acid in the morning, fasted | How your metabolism responds to the load and recovers |
| Start and end of the season | Total cholesterol in the morning, fasted | A long-term trend for the conversation with your doctor |
Making the values comparable
- Same conditions: same time of day, same interval since the last meal. Uric acid and cholesterol ideally in the morning on an empty stomach.
- Same sampling site: The instructions for use of the test strips specify capillary blood from the fingertip. How to obtain a clean drop is explained in Chapter 3.
- Keep notes: training, food, drink, sleep. Without this information, a value is hard to interpret later.
- Trend rather than single value: Every meter has some scatter. For β-ketones, for example, according to the instructions for use, 95 per cent of the results below 2.5 mmol/L lie within ±0.4 mmol/L. Small differences between two measurements are therefore not a signal.
- Strips and control solution: Each parameter has its own test strips. With the matching control solution you check whether device and strips are measuring correctly.
What the values cannot do
According to the instructions for use, the Metabol Pro test strips are intended for professional use. Glucose, ketone and uric acid strips are expressly not intended for the diagnosis or screening of diabetes or gout, nor as a basis for medication. The same applies correspondingly to total cholesterol in the case of lipid metabolism disorders.
For your training this means: the values help you to understand training load, nutrition and recovery better. If you feel ill, have symptoms or notice values that are persistently unusual, that belongs in the hands of a doctor.