About us

VentriJect is a Danish spin-out from Aalborg University in 2018 utilizing seismocardiography for determination of cardio respiratory fitness.

Our Mission

Giving a new dimension to fitness and general health check

Our passion is to contribute to make true the American Heart Association 2016-Statement of cardio respiratory fitness as first choice for health risk examination.
Our dedication is to develop a simple reliable method for measure of cardio respiratory fitness. 


Spreading cardiorespiratory fitness into a global standard for health examination

VentriJect is built on research and science in the healthy and diseased heart. We respond to society’s needs by transferring findings into general and personalized user applications.


Cardiorespiratory fitness (CRF) measured as VO2max may be determined by the VentriJect CRF Device. The Device measures vibrations arising from heart beats and transmitted to the chest. Each heart has its own signature relating to opening and closing of valves and the filling and contraction of the heart chambers. The system further includes an adhesive patch and communication to a smartphone.


Adhere the device to the distal part of the chest (sternum) when lying at the back and start the recording using the companion APP on a smartphone. The recorded cardiography signal is converted to a personal VO2max value being visible at the smartphone after some seconds.

Use cases for non-exercise VO2-max estimation

Ergometer estimation of cardio respiratory fitness will primarily be done in professional settings. Alternative indirect methods also generally require exercise.
The VentriJect method for indirect determination of VO2max gives opportunity for individualized determination of CRF, in all groups of people, teams of athletes, fitness in youth and for check of personal progression in fitness. All very quickly and without exercise.


Cardio Respiratory Fitness reflects metabolism and as the name indicates lungs and heart interact by supply of oxygen to tissues and organs and by elimination of carbon dioxide.
Human activity and work may be measured by the consumption of oxygen in metabolic units called METs determined in kcal/kg/hr. In rest the metabolic activity corresponds to 1 MET whereas running at high speed may correspond to levels above 15 METs.
Maximal oxygen capacity of a person means the maximal oxygen consumption until exhaustion and is called VO2-max. 1 MET correspond to a VO2-max-value of 3.5. 


Cardio respiratory fitness measured as VO2-max correlates not only to fitness but to general health. Many studies of fitness document that your VO2-max can be improved significantly with proper training regimes. A case study performed by the VentriJect method with 20 volunteers starting a twice weekly fitness program in eight weeks revealed in a mean of 10% improvement but individually up to 30% improvement of the cardio respiratory fitness.

Our Team

Peter Samuelsen and Stig Visti Andersen, researchers from Aalborg University: Samuel Emil Schmidt (associate professor), Johannes Jan Struijk (professor) and Kasper Sørensen (PhD student) and professor of cardiology: Peter Søgaard from Aalborg University Hospital, Department of Cardiology.

Peter Samuelsen


Samuel Emil Schmidt


Peter Søgaard


Stig Visti Andersen


Johannes J. Struijk

Senior Scientists

Kasper Sørensen

Head of Software

General Recommendations

The American Heart Association lists three recommendations for measurements of Cardio Respiratory Fitness during routine clinical visits.

The recommendations are cited from the article: 
Ross R. et al.: Importance of Assessing Cardiorespiratory Fitness in Clinical Practice: A Case for Fitness as a Clinical Vital Sign; Circulation 2016; 134:00-00.1

At a minimum, all adults should have CRF estimated each year using a nonexercise algorithm during their annual healthcare examination. Clinicians may consider the use of submaximal exercise tests or field tests as alternatives because these involve individual-specific exercise responses.

Ideally, all adults should have CRF estimated using a maximal test, if feasible using CPX (Cardiopulmonary exercise testing), on a regular basis similar to other preventive services. The specific age at first assessment and schedule for follow-up are yet to be established. However, patients with higher CVD risk profiles should have an initial test at an earlier age and be tested more frequently than patients with lower risk profiles.

Adults with chronic disease should have CRF measured with a peak or symptom-limited CPX on regular basis